# calibrix

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4

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• Rank
Peon

• Name
Chris
• Location
Burbank
1. ## Transfer UVs in world space to remeshed object?

As far as I know, during a remesh or poly reduce small distortion is expect as point positions have changed. This will mostly be evident at UV seams as those have to shift to account for the new mesh. I'm no expert at UVs though so maybe someone else will have a better idea.
2. ## Transfer UVs in world space to remeshed object?

Attribute transfer is what you need. But if you have UV seems those won't play nicely. You will need a vertex split node to break out the UV patches on your original model and then loop through each patch transferring attributes that way. That should keep your UV seams from breaking. Check this post for more info: https://www.sidefx.com/forum/topic/18890/
3. ## copying alembic transforms to packed pieces

Ah ha. I've figured this one out. What wonderful late nights in the office can do. For posterity: To translate the pieces you can use a single point wrangle. You need you pieces (duh) as a input, the animated alembic and a rest alembic (probably the same frame that made the pieces). You extract the 4x4 transforms from anim and rest. Use cracktransform to extract translate, rotate and scale. Offset you piece position by rest translate. Subtract animated rotation from rest rotation, so that your starting rotation is zero. Use the maketransform command with your animated translate, offset rotation and in my case I wanted to ignore scale so that was set to {1,1,1}. You can set position to your offset position * you new matrix. For each piece rotation you set the "transform" intrinsic to the matrix3 of your new matrix. // current position vector old_pos = @P; // get packed transform matrices matrix anim = primintrinsic(1, 'packedfulltransform', 0); matrix rest = primintrinsic(2, 'packedfulltransform', 0); // extract transforms vector anim_t, anim_r, anim_s, rest_t, rest_r, rest_s; cracktransform(0, 0, {0,0,0}, anim, anim_t, anim_r, anim_s); cracktransform(0, 0, {0,0,0}, rest, rest_t, rest_r, rest_s); // offset position vector pos = old_pos - rest_t; // offest rotation vector r = anim_r - rest_r; // create new transform assuming scale matrix m = maketransform(0, 0, anim_t, r, {1,1,1}); @P = pos * m; // create new rotation matrix matrix3 rm = set(m); setprimintrinsic(0, 'transform', @ptnum, rm, 'set');
4. ## copying alembic transforms to packed pieces

Hello, I'm working on a project and I'm a bit stuck on matrix transformation. I don't have a strong background in matrix manipulation. Here is what I am trying to do: I have a packed alembic that has been created from an external program. The alembic has a fullpackedtransform intrinsic that contains my translate, rotate, scale and shear data. I want to shatter this alembic geometry, pack the shatter pieces and use the original alembic transform to animate the pieces which will then be input into a rigid body simulation. I'm having trouble extracting the relevant data from the 4x4 matrix on the alembic. I can get my points to translate, but I don't yet understand how to make them rotate. I hope my diagram makes sense.
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