Hi Java 3D Folks,

I've been trying to create a basic CAD like program using Java 3D.

I have tried several (4) times, but each time I come to a point where it
really turns out to be crap, either in performance or in functionality.

This, I am half sure, is because of my inexperience with Java 3D (although
from all the attempts, I am getting to know *something* about Java 3D), and
because I am attempting everything from scratch rather than trying to find
utility code from other people.

The other half of me thinks its because Java 3D is not the right thing to
use.

Anyway, would there be anyone interested in helping me out, helping me
understand how to set things up, point out where to get utilities from, or
just the right way to use/code Java 3D?

My basic need is to have an interactive CAD-like system which has some very
basic functions like
1) Click on point to get (x, y, z) coordinate,
2) Click on 2 points to determine distance,
3) Click on 3 point to determine angle,

etc.

No need for complex CAD functions like Boolean subtraction of intersecting
objects, etc.

The objects I am interested in are "simple" polyhedra, plus some other
simple forms (Spirals, torii, etc.)

All I want to do is to be able to change their texture, move them around,
join them together (vertex to vertex, edge to edge, face to face), change
size/scale, orientation, etc.  The very basic stuff.

The reason I am not sure Java 3D is the right tool is because it takes *so
much code* to do anything....

My latest version fails because:
1) Runs out of memory for simple polyhedra...  For *each* *part* of the
polyhedron, I put the Shape3D under *several* transforms (spin, translate,
scale, orientation).  So, for a 120 triangular faced polyhedron there are
120 such sequence of transforms.  In part this was so that every triangle
gets drawn at the origin and then translated, spun, scaled, etc. into its
final position by the 120 individual transforms.  Another reason I tried it
this way was so that transparency worked better.  I find that when there are
intersecting polyhedra, transparency does not work very good unless you
split the intersecting polyhedra into parts out side (not intersecting) and
parts inside (intersected parts).
2) Saving a scene (for later import back into the app) is a nightmare....
Since scene graph objects are not serializable, I wrote my own import/output
functions. In short, its a mess. So many parameters to save.  *And* to read
back in....
3) Interactive functions is too primitive...
4) etc....

Anyway,  I am about to start again.

If several people are interested, I could setup an area on my web site for
development.  I don't mind posting code and screen snapshots.

To start, how would you folks setup and code polyhedra?

Any polyhedron would have
1) Line edges
2) Cylinder edges
3) Sphere vertices
4) Plane faces
all of which can be turned on/off (with a switch node), texture attributes
can be changed, etc.
and would need PickPoints (I would think) for selecting vertices, mid-edge
points, center of faces, center of volume.

Note that each element (each vertex, each edge, each face) would need its
own texture so that each vertex, etc. could be a different color.

Well, if anyone is interested, please let me know.

Anyone have examples of this already?

Any thoguhts on saving a scene graph to a file and reading it in later (with
all texture attributes for all objects)??

Bob Gray

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