ENGR1170 CHAP 5

MULTIVIEW SKETCHING II

Objectives 1. Identify normal, inclined and oblique planes in

multiview drawings2. Represent Lines, curves, surfaces, holes, fillets,

rounds in multiview sketches3. Identifying limiting elements, hidden features

and intersections of two planes in multiviews4. Visualize 3D objects as multiview projections

View Selection• Determine the best orientation for the object

– put imaginary glass box around object, surfaces of major features should be parallel or perp. to glass planes

• Define Front View– natural or assembled state, should show

characteristic shapes

• Determine the minimum number of views needed to completely describe object

View Selection• Determine which other views will have the

fewest number of hidden lines

• Always try to draw objects in their natural position

Edges and Planes• An edge, or corner is the intersection of two

planes, and is represented as a line on multiview drawings

• A normal or true-length line, is an edge that is parallel to a plane or projection and thus perpendicular to the line of sight

• Edge 1-2 in top and right side is a normal edge• Edge 1-2 is a point in the front view

Orthographic Projection• An inclined line is parallel to a plane of projection,

but inclined to the adjacent planes, and it appears foreshortened in the adjacent planes

• An oblique line is not parallel to any principal plane of projection, it never appears as a point or in true length in any of the six principal views.

Oblique Line• An oblique line is not

parallel to any principal plane of projection, it never appears as a point or in true length in any of the six principal views.

• Edge 3-4 is an incline line, note it is foreshortened in the top and right side view but true length in front view because it is parallel to the frontal plane

Normal Plane• An normal plane is parallel to one of the principal

planes of projection – It will appear true size, shape on one image plane and

appear as an edge on the other two.

Inclined Plane• An inclined plane is perpendicular to one plan of

projection and inclined to adjacent planes.– It cannot be viewed true size and shape in any of the principal

views. It does appear as an edge in the view where it is perpendicular to the projection plane.

Oblique Plane• An oblique plane is not parallel to any of the

principal planes of projection. – It does not appear true size and shape, or as an edge, in

any of the principal views.

•A: parallel to the frontal plane

•B: parallel to the horizontal plane

•C: parallel to profile plane

•D: inclined plane

•E: oblique plane

Angles•An angle is represented true size when it is in a normal plane

Angles• In (b) angle is not true angle because plane containing angle is not parallel to frontal plane.• In (c) right angles can be measured as 90 degrees in a foreshortened plane if one line is true length

Curved Surfaces• Only the far outside surface or limiting element of

a curved surface is represented in a multiviewdrawing