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Gettingstarted Lightup

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    Introduction

    LightUp aims to provide SketchUp users with a fast workflow to explorespaces and lighting. The motivation for LightUp is based on the oft quotedobservation that the more iteration that can be applied to a problem thehigher the likelihood of achieving a high quality result. LightUp is aboutplaying with light and shade in an environment that is tightly coupled to theunderlying model that SketchUp provides. LightUp relies on someunderlying physical basis for light transport but ultimately, like all software,

    it is a simulation which contains simplifying assumptions.IMPORTANT: The demonstration version of LightUp is time limited to 30minutes usage after which time it will cease to work and only normalSketchUp functionality will be available. Restarting Sketchup will reset thetimeout.

    System Requirements

    If youre already running Sketchup 6 or higher on your computer, youre95% of the way there. LightUp extends the functionality of SketchUp in a

    number of ways under the hood and makes use of your OpenGLcompliant video card. LightUp currently requires some OpenGL 2.0functionality to operate correctly. What does that mean to you? Well, ifyour video card is less than a few years old (after 2004), youre probablygood to go but were all at the mercy of the quality of our video drivers. Ifyour video card does not support the required OpenGL features, LightUpswitches to a very simple rendering mode that should work on all cards(you can if necessary also force this mode from the LightUp menu).

    The acid test is to run the free demo and see if it works. If it doesnt work,check you have Use Hardware acceleration selected in Sketchup

    preferences, ensure you have the latest OpenGL driver for you card orultimately go splash out on a less antique video card.

    Registration Key

    The first time you run SketchUp after installing LightUp you will beprompted for your 32 character Registration Key you were sent by email.You can reset the Key from the Tools->LightUp menu.

    Getting Started with LightUp v1.10

    Copyright (C) 2010 Adam Billyard All rights reserved! 1

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    Contents

    Setting up 3Example Walkthrough 3Menu Items 11Area Lights 11Point Lights 12Query Tool 12Preferences 14TourTool 18Shading Parameters 19Lightmeter 21Exporting Stills 22Exporting Movies

    23

    Exporting FBX files 23Exporting LightUp Player files 23Scenes 24Caching 24Masked Textures and Opacity 24Materials 25Material Markup 26Skybox 27Specularity and Reflections 28Known Issues 31Contacts 31

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    Setting up

    LightUp requires minimal setup, however for completeness well coversome of the settings and preferences. The LightUp toolbar consists of 3buttons:

    Bring up the Preferences dialog for the current model

    Invoke the QueryTool which allows setting of light sourceparameters and lighting parameters. Alt/Apple + leftclickwill add a new PointLight source to your model.

    Go! Update lighting and switch to realtime lit rendering ofthe current model using the TourTool - the fun one!

    Example Walkthrough

    Download this very simple model of 2 rooms from the website:

    http://light-up.co.uk/resources/examples/example0.skp

    Open the model in SketchUp and you should see something like this:

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    Circled in red on the left is a large 2m x 2m area emitter of 3000 lx that willact like a window letting in daylight. In the righthand room are 2 SketchUpComponents representing PointLightSources and a small recessed fixturewith a narrow beam.

    LightUp marks the location of point lights using specially named SketchUpComponents. Any Component with a Definition name starting withPointLightSource will be treated as marking where you wish to place alight source.

    Open the SketchUp Component dialog, click the Home icon to showwhat components you have in your Model and drag a newPointLightSource into your model. A default PointLightSource Componentis automatically added to your model by LightUp. It looks like this:

    NB Youll notice it is not the same as the ones in the example. This isbecause the example uses an older style of Component with a Definitionname starting with PointLightSource also. Anycomponent can be usedto mark the location of a point light as long as the Definition name beginswith PointLightSource

    TIP:Query tool has a shortcut which allows you to place lightsources using Apple/Alt + mouseclick on any part of yourmodel without having to open the Component browser. Try it.

    Press Tourtoolto perform the lighting calculations and switch to realtime

    rendering mode.

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    Now return to SketchUp by selecting a regular SketchUp tool from the toolpalette (eg the Select arrow).

    Next try using the Querytoolto hover over light sources to see the tooltipinformation about the light source. LightUp will show light sourceinformation in a tooltip and give an indication how far light will travel fromthe light based on its power.

    You can mouse click on the PointLightSources and area light sources toalter the power. Try moving some lights around or change their color

    using the SketchUp color picker:

    - Select Querytool

    - Click on a PointLightSource to show the edit dialog:

    - Click on the color selector to change the light color.

    - Change the Lumen rating in the text box. 1200 Lumen is the defaultvalue which is very approximately the brightness of a 75 Wattincandescent bulb.

    TIP:Shift + mouse click to select multiple LightSources andapply edits simultaneously.

    The simple Lumen rating will shine equally in all directions. These kinds oflights are often called Omnilights.

    Real world light sources do not emit light equally in all directions. Theyhave openings for power, they have enclosures that shield lighting incertain directions, reflect in others etc. In order to capture this detail, allmanufacturers of lights provide, for each of their products, a (free todownload) file that exactly captures how light is emitted in each direction.IES files are produced in testing laboratories and contain exact readings

    for each light, so by using these IES files, you get not only more accuratelighting in LightUp, but often times more interesting lighting effectsbecause of the umbra that real lights produce.

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    So setting an IES file on a PointLight can make it behave like a spotlight, astadium light, an LED light rather than a constant value in all directions.

    Download and save this IES file from the website to experiment:

    http://light-up.co.uk/resources/examples/GDL002-200-XPW-001N.IES

    Using the Query tool you can click on a PointLight and set it to use the IESfile for lighting by clicking on the yellow ... file Chooser button on therighthand side:

    LightUp has a built-in IES file browser which shows all the key information

    contained in the IES files without having to render them.

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    TIP: You can use the mouse wheel to scroll through files orjust hold down the mouse button on the lefthand panel anddrag up or down.

    Navigate to a IES file of your choice (or the IES file you downloaded) andpress OK.

    Now when you hover with Query tool over this light source, youll get ayellow mesh showing the profile and power of your light source.

    Pressing Tourtool shows the dramatic effect of using IES files for simplelight sources:

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    :TIP: Keeping your IES files together with your SketchUp filescan be error-prone if you copy files around but forget the IESfiles. LightUp always checks for a folder called Lightswhere your model is stored so you can keep the IES files youneed for the model all together in one place.

    Here is another simple scene modeled in SketchUp with the LightUptoolbar ready for use. You can download the model:

    http://light-up.co.uk/resources/examples/lobby.skp

    Open the model in SketchUp and you should see something like this:

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    In Preferences we choose Direct Lighting and Blend with AO and checkUse Sun.

    Click on the TourTool button will perform any lighting calculations andswitch to realtime rendering mode.

    Because were using AO + Direct Lighting, youll get a lack of definitionwith everything too bright. Open Preferences and in the AO section andchange the Multiplier to 0.5 to reduce the amount of AO. Press Tourtooland LightUp will rescale the resultswithout the need for relighting.

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    By pressing RETURN youll bring up the capture dialog from which youcan export images, skybox, movies, model files as well as export directlyto the LightUp Player format.

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    Menu Items

    The Sketchup menu Tools->LightUp contains a number of controls forusing LightUp.

    Export Preferences: Saves your current model preferences to a file soyou can share with others.

    Import Preferences: Loads preferences from a file overwriting your currentsettings.

    Remove All LightUp Info: Strips out any additional information thatLightUp has added to your Sketchup file such as Area light settings,Material settings.

    OpenGL Info: Opens the Ruby console and prints technical details of yourgraphics card. This is used primarily for fault finding.

    Reset Registration Key: Resets your key and allows you to re-enter it.

    Force Simple Rendering: LightUp automatically choose which mode touse based on your graphics card capabilities. However, you can forceLightUp to use a simple mode using this menu item.

    Default is Doublesided: Sets the doublesided Preferences for all newlycreated documents.

    Removed Unused Hierarchy: Many Sketchup objects are constructed ofGroups and Component Instances that while useful for editing, are notused during Tourtool. LightUp can removed these hierarchies to increaseperformance.

    Area Lights

    Area lights are identified by LightUp through some markup on eachSketchUp materials. This extra information is added interactively usingthe QueryTool by clicking on a face with a material. NB You must add amaterial to a face in order to edit it - you cannot edit the Defaultmaterial.

    This material can then be marked as an emitter material along withparameters for power, spread and sampling density. Power is in units oflux (lumen/m2), Spread is in degrees from the face normal and lastlyDensity allows control of how much sampling of the emitter LightUp shouldperform. Generally this parameter should be left at 1.0 but if you find

    some hotspots on surfaces near the area emitter you might want toincrease this. Conversely, it is sometimes desirable to set density=0.0 tohave a single sample in the center of the area emitting face.

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    The power of an area light is derived both from the material parametersand the area of the face. A large area emitter introduces more energy intothe scene than a small one.

    Point Lights

    Point lights are identified by LightUp using a custom Component whichcan be dragged into your model. The position, color and power of the lightcan all be adjusted. It can be found in the Components browser (go toWindows -> Components) and is called PointLightSource.

    In fact any component whose Definition begins with the namePointLightSource will be treated as a Point Light by LightUp. This allowsyou to create custom geometry that will be a placeholder for your lightsources if you so desire.

    A shortcut for adding PointLights is to select the QueryTool shown belowand hold Alt/Apple and left mouse button to place a PointLightSource onthe surface youre current hovering over.

    Query Tool

    The settings of an area light material or a point light can be adjustedusing the QueryTool as well as various other lighting attributes. Select thequery tool and click on a light source to pop-up a dialog of parameters toedit. Shift-click will add/remove items to the current selection for editingmultiple items. NB the color of a light source is derived from the color it isassigned in SketchUp so all the normal SketchUp tools can be used forthis.

    Clicking on a PointLight will bring up adialog to edit its parameters. You can entera simple Lumen value for the light to giveeven distribution of light (an Omni light); a75-watt incandescent bulb produces around1200 Lumen. Or select an IES photometricdata file for more control over the directionand power the light source provides.

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    Clicking on a face with a (non-default)material will bring up the Material dialogwhere you can set a variety of parameterswhich will apply to all faces using thismaterial. Check Emitter to make all facesusing this material Area Emitters asdescribed earlier.

    In addition there are a number of otheruseful settings.

    Always fully lit will force drawing the face with no shading which is usefulto create fake emitters. Faces that are bright like emitters but are notarea light sources.

    Dont cast shadows ensures faces using this material dont block light.You may have an opaque texture of a window but still want sunlight to beable to pass through the faces. NB If you wish a whole object to not blocklight, you must use the cast shadows setting in SketchUps Entity Info.

    TIP: Set Dont cast shadow / uncheckcast shadows onDynamic Components that will be moving to avoid leaving aphantom shadow when they move.

    Low density is useful in situations where you have a large area thatdoesnt need high resolution lighting and can thus benefit lighting times bybeing marked for low resolution lighting.

    High density conversely increases the lighting just for those faces usingthis ,material. If you need more shadow clarity in just a small area but donot wish to increase Resolution generally, this is a useful setting.

    Additive glow effects how the geometry is rendered. It is lit in the sameway but rather than being blended into the scene with the other geometryit is added to the pixels increasing their brightness.

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    Preferences

    LightUp preferences aredivided into 3 panels (Quality,Lighting and Viewing) along witha Resources panel containinglinks to web resources forconvenience. (Tip: Clicking onthe Panel titles will collapse it toreduce the size of the window).

    The first panel is Qualityandsimply controls the resolution ofthe lighting data. More resolutiontakes longer to calculate.

    Doublesided Do you wishLightUp to light and draw boththe front and back material ofeach face. For realtimeapplications, models arecommonly created just using thefront material. Just using thefront material will reducelighting time and increaseTourtool framerate, however themodel needs to have beenconstructed with this in mind.The Default for this option ischecked ie process both front and

    back of each face. This default can be set from the Tools->LightUp menu.Use Selection By default LightUp will just light the part of your modelcurrently selected - or the entire model if nothing is selected. Uncheckingthis box will make LightUp ignore any selection and always light yourwhole model. The question of which to choose is down to your ownpersonal workflow.

    Resolution. LightUp calculates how much resolution your model requiresusing some basic heuristics. The Resolutionfield works very like theSketchUp value input field; it accepts input of the form Nx meaning Ntimes whatever resolution LightUp came up with for your model. As a rule

    of thumb, leave it at 1x or 2x while checking things are working and raise itto 4x or 5x if you need (often the result you get with the default will be justfine).

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    Once youre more comfortable with LightUp, it is often easier to enter anexact value for Resolution. This value (in units of your choice) will be usedto control the smallest light sample. For example, if youre lighting aaverage sized room, you may want to calculate the lighting at 6 intervalsso youd enter 6 (or 15cm or 0.5) in the input box.

    Ignore cacheforces LightUp to regenerate all data irrespective of theexistence of cached results.

    The second panel is Lighting.

    The drop down menuselects AmbientOcclusion (sometimes referred to as clayrendering), Direct Sources or Lux Contours.

    Lighting mode: Ambient Occlusion

    Ambient occlusion (AO) is a common technique for approximating how

    much of the ambient light in the scene reaches a surface by examining thesurrounding geometry. The result is a scalar value that can be used tocontrol shading.

    The first control is how far to search for surrounding geometry. Thechoices are Interior, Exteriorand Custom. Interioris a preset to be usedinside, Exteriora preset for outside shots and Customallows specifying aabsolute distance.

    The reason for these cutoff distances is that inside a building all thesurfaces are near something which would result in a black image (try it

    using a closed room and chooseExterior

    ), so it is common to provide acutoff distance beyond which the surface is considered not occluded.

    The result of AO calculations are used to blend between 2 user-definedcolors. Bright color and Dark color. You can edit these in Preferences.

    LightUp offers 3 different ways this AO factor can be used to shadegeometry:

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    Normal Blend: The surface normal is used toblend between the current Bright & Dark colorsand this is scaled by the AO result. An optionalscale factor is also applied.

    Linear Blend: The AOresult is used to blend between linearly thecurrent Bright & Dark colors. An optional scale

    factor is also applied. In the image weve useda bright green for the Dark color fordemonstration purposes.

    IBL Blend: The surface normal is used tolookup the HDR color in an image (so calledImage Based Lighting or IBL) and this is scaled

    by the AO result. This technique gives lightingwhich exactly matches the skybox backdrop forvery natural looking results.

    Constant: The current Sky & Ground colors (orjust the Background color if Sky is not enabled in Sketchup Style) is used.This is a fast way of getting some fill-in ambient. An optional scale factoris also applied.

    Lighting mode; Direct Sources

    The (default) mode applies all light sources to your model

    Use Hidden Lightscontrols whether to ignore lights that are hidden. Usefulfor phantom lights.

    Use Suncontrols whether to use the sun as a light source. A SunMultiplier allows manual tweaking of the power of the sun along with aTurbidity control to alter the haziness of the sky.

    Here is the same model rendered with turbidity=0.1

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    and turbidity=0.9

    Screen with AOcontrols whether to combine Ambient Occlusion data with

    Direct Lighting data or just use a simple constant ambient term.

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    Lighting mode: Lux Contour

    Lighting is performed as normal but the results are displayed using alogarithmic pseudo-color ramp which makes it easier to find and analyzelight distribution problems.

    Two further modes are available here for light analysis work.

    The Daylightmode is a simple overcast sky model with a lux scaling.

    The Insolationmode provides realtime measuring of Kwh/m2/day alongwith this value with respect to the current surface the lightmeter is over.

    The third panel is Viewing

    Lighting onlycontrols whether to blend material colors and textures withlighting data.

    Pause AnimationHalts any material animation and DC animations so youcan get precise Stills.

    Show Skyboxcontrols whether to draw an enclosing skybox which candramatically enhance the sense of presence as one navigates the scene.

    Camera Collisionenables collision in a very similar fashion to theSketchUp Walk tool.

    Apply Gravityenables applying gravity to the camera should you walk off aledge.

    Apply Inertiaenables allowing the camera to slowly come to rest ratherthan stop immediately. It gives a softer experience for touring models.

    TourTool

    Switching to the TourTool, updates the lighting for your model andthen allows smooth navigation to examine the lighting youve set up.Controls are:

    Look Around## # Left Mouse Down + Drag

    Pivot Around## # Left Mouse Down + Drag + Alt

    Dolly # # # # Left Mouse Down + Drag + Shift

    Move# # # # Arrow keys

    Exit Tour Tool# # Escape key or choose another tool

    Toggle SketchUp view# Middle Mouse Down + Drag

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    NB When dollying the camera, LightUp will attempt to estimate the heightof the camera from the ground and show it in the lower right corner of theSketchup window so you can easily get a realistic placement of thecamera. If you have gravity enabled, this height is then maintained as youtour around the model.

    Shading Parameters

    During Tourtool you can double-click on amaterial to bring up the Shader editor. This

    allows you to change some basic shadingparameters that will apply to the material youclicked on. These will be saved inside yourSketchup model.

    The Metal checkbox controls whether thereflections are effected by the material color.A dielectric surface like plastic/wood reflectsthe color of the source, whereas a metalsurface attenuates reflections by its owncolor.

    There are a number of common presets forIndex of Refraction (IOR) as well asaccepting absolute values in the input box.

    By default LightUp will create a normalmapautomatically from the Material texture. Thiscan be overridden by loading a bumpmapand/or specular map from a file using the filechooser.

    Alternatively, you can type in floating

    point values into the Specular andFresnel edit boxes to set it to aconstant. (eg 0.25) or type a space toreset to the original values.

    The base color of the material can be adjusted in realtime using theRed,Green,Blue sliders. NB These color tweaks are applied only while inTourtool mode. The Sketchup materials are not altered. Not only is it

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    useful to change colors while in Tourtool for aesthetic reasons, its alsouseful to turn down the material color to black so you can see just thecontribution of the specular bumpmaps to your image.

    The second panel is Texture Animation. This controls how LightUpanimates the UV coordinates of your materials. You can choose thewaveform and how it is applied to the UVs.

    Download this simple example from the website here. Youll need to unzipit to create texanim.skp and a Textures folder. Press Tourtool and now

    double-click on the tiled floor to bring up the Texture Animation dialog.

    Choose Ramp as the waveform from thefirst drop-down menu and the floor will startflowing to the left. Try typing in a differentAngle (in degrees) to alter the direction.

    Now drag left and right inside the waveformwindow to change the frequency of thewaveform and thus the speed of the flowing texture. A frequency of 2Hzmeans the texture will scroll its entire width 2 times each second.

    Change Frequency## Drag left and rightChange Amplitude# # Drag up and down

    Change Phase# # Shift + Drag left and right

    Change Baseline# # Shift + Drag up and down

    Now choose the Sine waveform from the dropdown menu for a differenteffect.

    The second dropdown menu allows control of what aspect of the UVs iseffected. It defaults to Translate, but you can chooseScale or Rotate.

    Combining waveforms and different transforms can produces manyeffects.

    The last control to mention is Steps. Normally the waveforms aresmooth functions that vary over time, so choosing a Ramp waveform +Translation causes the texture to flow smoothly. However sometimes it isuseful to have the animation move in distinct steps. A good use of Steps isapplying a texture that consists of 8 images side by side that form a shortmovie loop. You want the texture to jump from frame to frame not slidesmoothly between them. By choosing a Ramp waveform, Translation andsetting Steps=8 you can achieve this.

    The second panel is Color Animation.. This works in a very similar way toTexture Animation described above. To get started, from Tourtool modedouble click on a material and choose a Square wave from the dropdown

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    menu. This will make the material flash on and off at 1 time a second(1Hz). Choosing other waveforms and adjust them to get the effect youwant.

    Lightmeter

    During Tourtool you can get realtime illuminance readings byholding down the Alt/Apple key and pressing the left mouse button.

    The lux value at the point your mouse is over will be given allowing a fastcheck on simulated lighting levels.

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    Exporting Stills

    While its all good wandering aroundour creations and experimenting withlighting, we need to be able togenerate images that can be used forpresentations. Simple screenshotsmight suffice but at printedresolutions they lack sufficient fidelityand generally look poor.

    An additional feature of LightUp isthe ability to generate very highresolution anti-aliased images ofwhat youre seeing on screen. Pressthe Return key while using Tour Toolwill pop-up the Capture dialog if it ishidden.

    Simply choose you resolution andpress Still. You will be prompted fora Savefile name to use. LightUpsaves using the TIFF image format.

    You can also choose to save thedepth information for the image at thesame time. This will be saved as afloating point TIFF image with theaddition _depth added to yourfilename. Depth images arecommonly used by post-processingin applications such as Photoshop toidentify the depth of each pixel soaccurate montages can be created.For example replacing the sky behinda building.

    Another option is to use the cubemap generator. It will produce 6 squareimages centered on your current position from which you can easily createa Quicktime VRfile to allow others to get a sense of a space interactivelywhile retaining a small file size. Choose file naming to use appendednames or appended numbers and press Cubic... and youll be promptedfor a base filename/folder t which the six images will be saved.Alternatively you can save the 6 images as a single vertical strip.

    The demo version of LightUp will watermark your export.

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    Exporting Movies

    LightUp can generate high resolution anti-aliased movies too. Chooseyour movie resolution and options and press Movie.. to begin recording.You will be prompted for a Savefile name to use. You can now navigatemanually, or use Scene animation to generate your movie. Recording willcontinue until you press RETURN at which point the movie will beprocessed into a standard AVI file or Image Sequence depending on youroptions.

    IMPORTANT The AVI file contains a full color, non-compressed 30Hzmovie that will need to be compressed down to a reasonable file size todistribution and play smoothly.

    The demo version of LightUp will watermark your export and limitsrecording to 5 seconds.

    Exporting FBX files

    LightUp can generate an Autodesk FBX compliant file containing your

    Tourtool geometry including all the lighting. The object hierarchy isretained, all textures are exported and an optional stub name (defaultlmap-) for lighting textures allows easy import into other applications.

    The resulting FBX file can be imported into other applications that supportmultiple UV coordinates and multitextures such as Maya or Unity.

    Exporting LightUp Player files

    LightUp can generate .luca files from you Tourtool results. These files

    contain your geometry, lighting and Scenes youve defined and can begiven to other for viewing using the free to download LightUp Player (seewww.light-up.co.uk/player ).

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    Scenes

    LightUp works well with SketchUp Scenes and these can be setup insideTourtool or beforehand. Animating between Scenes will all be honoredwhen recording movies.

    Caching

    LightUp is very fast at performing illumination calculations, however for acomplex model with many light sources it can take a few minutes. In orderto reduce the wait, LightUp automatically saves partial lighting results in afile (called lightup.cache) so when you ask for the same lighting again, itcan pull out the partial results and very quickly re-create the lighting. Thishappens automatically (unless you select Ignore Cache in Preferences)and allows you to experiment with different lighting parameters quickly.NB Remember to Save your model after lighting is complete as this willensure that LightUp can find your cached results next time you load thatmodel.

    Masked Textures and Opacity

    Light transport is effected by passing through non-opaque materials inLightUp. The opacity of a material is determined by the texture map alphachannel and by the material alpha as set in SketchUp.

    You can download the model here that shows sunlight being filteredthough a texture.

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    Materials

    LightUp takes it material information from the SketchUp model, preferringany primary sourceit can identify over embedded information. Thismeans that for a textured material, LightUp first tries to load the originaltexture directly from the filepath provided by SketchUp. If this fails it willlook in the SketchUp Materials folder .skmfiles for the texture. If this failsit will extract the texture information cached inside the SketchUp modelfile.

    Having acquired the base albedo texture, LightUp then checks to seewhether you have a specularmap/normalmap previously setup. If it doesnot find one it will search the same folder it found the texture file for acorresponding map by appends the word _uvlmap to the texture name toload a combined normalmap and specularmap. If this doesnt exist, itappends _specmap to load a grayscale specularity map.

    During rendering, the normalmap and specularmap are used to addspecularity to surfaces. This involves calculating where rays emanatingfrom your eye-point would bounce off the surface into your scene - anexpensive operation - and one that largely contributes to why traditionalraytracing (which LightUp does not use) can be quite slow. In order tokeep things whipping along, LightUp uses multiple Irradiance Cacheswhich are probed instead. Irradiance caches are added in the samemanner as Point Light Sources. i.e. they are custom components that canbe dragged and positioned in your scene. They are processedautomatically and require no further intervention. If you have no Irradiance

    caches in your model, LightUp will try and use your skybox as a cache,which for exterior scenes will often be what you want.

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    Material Markup

    LightUp uses markup on the material name to indicate attributes related toprocessing and rendering. These attributes can be combined at will toprovide a large amount of control. All of these can be set by using theQueryTool and clicking on a face with a material.

    Heres an example of using material markup to control lighting andrendering of a very simple scene lit by sunlight:

    Now we change the standard SketchUp material called Brick_Rough_Darkto have the attribute Cast no shadow:

    Notice the brick block now does not stop sunlight to the floor behind it,however it continues to receive shadows. The attribute Cast no shadows

    is exactly analogous to Sketchups Cast Shadows in the Entity Info panelbut differs in that it is per material not per face

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    .It is sometimes useful to have some faces not be shaded but still be partof the rendering. An example would be a fake emitters; surfaces thatlook bright but dont actually contribute to the illumination of the scene. Ifwe now change the material by checking Always fully lit, we get:

    The brick block is now not shaded and casts no shadow.

    Skybox

    A skybox is, as implied by its name, a closed box rendered around thecamera and moving with the camera to give the impression of anenvironment infinitely far away. Its common use is for sky, clouds anddistant (i.e. non-parallax) objects like mountains and buildings.

    LightUp accepts a latitude/longitude panorama image in either LDR andHDR format of any size or a traditional skybox set of 6 square, power of 2sized images for each of the 6 faces of a box. This means the skyboximages must be one of 32x32,64x64,128x128,256x256,512x512 or1024x1024.

    The name of the skybox file to use is set in the preferences for the modeland should be the complete filepath to one of the face images. LightUpwill find the others from there if its skybox set.

    TIP: Keeping your Skybox files together with your SketchUpfiles can be error-prone if you copy files around but forget the

    skybox files. LightUp always checks for a folder calledTextures where your model is stored so you can keep theskybox files you need for the model all together in one place

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    The filenames for each image of each face of the box are specially named.They must end in left, right, up, down, back and front. A set of 6images in .jpg format for a skybox called my_skybox_image_ wouldconsists of:

    my_skybox_image_left.jpg

    my_skybox_image_right.jpg

    my_skybox_image_up.jpg

    my_skybox_image_down.jpg

    my_skybox_image_back.jpg

    my_skybox_image_front.jpg

    You can create Skyboxes using LightUp itself by placing the camera atyour chosen viewpoint, starting Tourtool and choosing Cubic... andfront,right,up... format which will create 6 square renderings around thecurrent camera location. These can be used subsequently as a skyboxinside LightUp or converted to a Quicktime VR format.

    Specularity and Reflections

    Very broadly lighting effects can be classed as View independent andView dependent. That is, lighting which doesnt change regardless of theviewers position and lighting which changes as the viewers positionchanges.

    Diffuselighting is due to light bouncing off a surface in a uniformdistribution (randomly scattered) and is thus view independent and can becalculated once and is valid for any viewpoint.

    Specularlighting is due to lighting bouncing off a surface in a morecoherent way and so is view dependent and cannot be precalculated.

    LightUp renders the Diffuse lighting and the Specular lighting (if any)together making use of the additional material textures to do so.

    Consider the scene below with a platform with a simple ashwood texturemap called ashwood.png applied:

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    A skybox is setup for the scene in LightUp Preferences, and Sunlit inenabled and were ready.

    Switching into Tourtool and dropping the camera down for some moredetail and we get:

    Now if we double click on the ashwood platform material and adjust thespecular slider we get this:

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    NB This reflection is simply reflecting the skybox and is the simplest formof reflections in LightUp.

    Download this simple example from the website here. (It is the same

    model as used for the Texture animation example). The concrete planteris grouped as an object and just above the water surface an IrrCache isplaced. LightUp will search your model for IrrCache to bind to groups/Component Instances and will find this IrrCache and use it in preference tothe simple skybox. The result is that the brick wall is reflected nicely in thewater.

    Tip: Place IrrCaches as close as possible to where thereflections are being generated to get accurate placement.

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    http://www.light-up.co.uk/resources/examples/texanim.ziphttp://www.light-up.co.uk/resources/examples/texanim.zip
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    Known Issues

    Cant handle multiple open windows on Macintosh.

    Objects with non-orthonormal local transformation give incorrectreflections.

    Contacts

    website:# http://www.light-up.co.uk

    forum:## http://www.light-up.co.uk/forumemail:## [email protected]

    Getting Started with LightUp v1.10

    mailto:[email protected]?subject=LightUp%20Demomailto:[email protected]?subject=LightUp%20Demohttp://www.light-up.co.uk/forumhttp://www.light-up.co.uk/forumhttp://www.light-up.co.uk/http://www.light-up.co.uk/

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