Adt2
Draw a Hull in Rhino From a Table of OffsetsTurn an existing table of offsets into a faired hull using Rhinoceros 4.x.
Written By: Andrew Taylor
Draw a Hull in Rhino From a Table of Offsets
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INTRODUCTION
This guide will demonstrate the steps required to turn an existing table of offsets for any size boatinto a faired hull using Rhinoceros 3D software.
Steps include:
Converting the table of offsets into a format suitable for use with RhinoTweaking Rhino's settings to make it easier to useEntering the points into Rhino and creating curves through themFairing the drawn curves
TOOLS:Rhinoceros Software (1)
Draw a Hull in Rhino From a Table of Offsets
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Step 1 — Convert offsets to decimal
Offsets are typically given in feet-inches-eighths notation. In the figure at left, the keel at station 0is shown as 6-4-0 - or "6 feet, 4 inches, and 0 eighths of an inch" - above the baseline.
To make it easier to enter the offsets into Rhino, convert the offsets into decimal inches (i.e. 6-4-0becomes 76.000").
Use a spreadsheet to do this easily. Create a table like the one shown in the figure. Make surethe feet, inches, and eighths are each entered into their own cell.
Create a new table to the side. Use a formula [=sum(FEET_CELL*12)+INCHES_CELL+(EIGHTHS_CELL*0.125)] to convert the offset notation to a decimal number.
Repeat this step for each section of the table of offsets (i.e. Heights Above/Below Baseline, Half-Breadths from Centerline, Diagonals, etc.).
Tip: When converting from feet-inches-eighths notation to decimal, instead of using stationnumbers (0,1,2, etc.), convert the stations to inches (0, 36, 72, 108, etc.). The distance betweenstations will be shown on the table of offsets or on the accompanying drawings.
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Step 2 — Set up Rhino
Open Rhino. If the Startup Template window appears, choose Large Objects - Inches and clickOpen.
Select Tools>Options.
Select Units. Change the values as necessary so they match the figure at left.
Select Page Units. Change the values as necessary so they match the figure at left.
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When finished, you will have a faired 3D hull model in Rhino, suitable for further use in design and/orconstruction.
This document was last generated on 2017-06-19 08:19:42 AM.
Step 3 — Set up Rhino (continued)
Select Grid.
Select All Viewports.
Change Grid extents to somethinglarger than the length of your hull.
Set Minor grid lines every 1".
Set Major grid lines every X minorgrid lines, where X is the stationspacing in inches (i.e. 36 for 3'station spacing).
Select Show grid lines, Show gridaxes, and Show world axes icon.
Set Snap spacing to 0.1", andthen click OK.
Step 4
No instructions yet.
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