| 68 |
|
Note that this is strictly for ease of identification, and has no |
| 69 |
|
real meaning as far as the geometric description goes. In contrast, |
| 70 |
|
the transform entity is very significant as it determines how enclosing |
| 71 |
< |
objects are to be scaled and placed in the final description. |
| 71 |
> |
objects are to be scaled and placed in the final description. Hierarchical |
| 72 |
> |
contexts may be nested in any way, but should not overlap. |
| 73 |
|
|
| 74 |
|
Without further ado, here are the proposed entities and their interpretations: |
| 75 |
|
|
| 97 |
|
sph vc radius sphere |
| 98 |
|
cyl v1 radius v2 truncated right cylinder (open-ended) |
| 99 |
|
cone v1 rad1 v2 rad2 truncated right cone (open-ended) |
| 100 |
< |
prism v1 v2 v3 .. length right prism (closed solid) |
| 100 |
> |
prism v1 v2 v3 .. length truncated right prism (closed solid) |
| 101 |
|
ring vc rmin rmax circular ring with inner and outer radii |
| 102 |
|
torus vc rmin rmax circular torus with inner and outer radii |
| 103 |
|
xf [xform] begin/end transformation context |
| 263 |
|
and a length value. The prism will be extruded so that the end-face |
| 264 |
|
points outward, unless the length value is negative, in which case the |
| 265 |
|
object is extruded in the opposite direction, resulting in inward- |
| 266 |
< |
directed surface normals. |
| 266 |
> |
directed surface normals. If surface normals are specified for the |
| 267 |
> |
vertices, they will be applied to the side faces but not the end |
| 268 |
> |
faces, and they must generally point in the appropriate direction |
| 269 |
> |
(i.e. in or out depending on whether extrusion is negative or positive). |
| 270 |
|
|
| 271 |
|
A sphere, cylinder or cone with negative radii is interpreted as having |
| 272 |
|
an inward facing surface normal. Otherwise, the normal is assumed |
