Nikolai, Thanks for your bug report and test program. Your program reveal the same bug as reported in BugId : 4751283 - Transform3D.normalize() and Matrix4d.get(Matrix3d) permute matrix columns.
The SVD algorithm that Java 3D uses will sort the columns of the output matrix by descending order of their scale factors. This is useful for many types of problems, but is inappropriate for the normalization of rotation matrices.
BTW, BugId : 4751283 is still open and I'm able to view it with our internal bug tool. I will try to resolve the discrepancy with BugParade.
thanks, Chien Yang Java 3D, Sun Microsystems Inc.
Nikolai V. Chr. wrote:
import javax.media.j3d.*; import javax.vecmath.*;
public class scaleTest {
public scaleTest () { }
public static void main (String[] args) { Transform3D t1 = new Transform3D(); Transform3D t2 = new Transform3D();
Vector3d s1 = new Vector3d(1.0,1.0,3.0); Vector3d s2 = new Vector3d();
t1.set(new AxisAngle4d(0,1,0,1.57));
t1.setScale (s1); t1.normalizeCP ();
t2.set(t1); // even if normalizeCP is flawed this should make t1==t2 t1.getScale (s1); t2.getScale (s2);
System.out.println(s1+" == "+s2); } }
Expected Output:
(1.0, 1.0, 3.0) == (1.0, 1.0, 3.0)
Actual Output:
(1.0, 1.0, 3.0) == (2.9999991544849074, 1.0, 1.0000025365417038)
Why normalizeCP() is important when we have normalize():
Because normalize() also fails, see bug 4751283 "Transform3D.normalize() and Matrix4d.get(Matrix3d) permute matrix columns.": http://archives.java.sun.com/cgi-bin/wa?A2=ind0209&L=java3d-interest&D=0&I=-3&P=30861
So I am left with no working normalize method?
I will be grateful for any code suggestions able to cope with non-uniform scales.
Btw. Mark Hood's "conditionScale" doesn't always work, many times AFFINE transforms are still AFFINE after running it.
Btw2. Rather strange Sun has removed bug 4751283 from the BugParade. Does that mean they regard it as closed?
Regards Nikolai
---------------------------------------------- Nikolai V. Christensen, Computer Engineer, Simulation and Training department IFAD, Forskerparken 10A, DK-5230 Odense M Denmark, EU Phone: +45 63 15 71 31 Fax: +45 65 93 29 99 WWWeb: http://www.ifad.dk e-mail: [EMAIL PROTECTED] ----------------------------------------------
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