Resizing 3d objects

Question

Hello! I'm new at java3d and i'm researching for my university project. I have the following question: how can i resize a object imported from a .obj file? There is any way to do that? Suppose i've a .obj that i want to load to my project but i need to resize it to be with the same width but a different weight.
I've the code above:
Transform3D objLocation = new Transform3D();
objLocation.set(p.scale, new Vector3d(p.posx, p.posy, p.posz));
//returns a scene with the object i want
Scene s = ObjLoad();
TransformGroup newScene = new TransformGroup();
newScene.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
newScene.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);
newScene.setTransform(objLocation);
newScene.addChild(s.getSceneGroup());
objSpin.addChild(newScene);
The solution i figured out makes possible to place the object where i want and scale it, but it doesn't work because i want to redimensionate the object and not to scale it...
I would appreciate any help!
tks in advance
ps: sorry about the poor english, hope you understand it
Bruno
Portugal

Answer 1

Java3D uses a 4x4 matrix for these operations. Scale and rotate happen in the upper-left 3x3 matrix.
This matrix doesn't affect translation at all.
I think the 3x3 matrix that do what you want is the following :
xscale 0 0
0 yscale 0
0 0 zscale
so you just have to create your TransformGroup using this Transform3D.
Matrix3d scalematrix = new Matrix3d(xscale, 0, 0, 0, yscale, 0, 0, 0, zscale);
Vector3d translationvector = new Vector3d(xtranslation, ytranslation, ztranslation);
Transform3D t3d = new Transform3D(scalematrix, translationvector, 0d);hope this will help !
c ya
GnG