AWS Thinkbox Discussion Forums

custom channels

1)how can i add one custom channel into other magma node,for example -i want to use custom channel-A from first magma node of same prt volume in second magma with custom channel-B.
Error_Magma Channel “name of custom channel” Not Available in this PRT Object.
2)where is inputtexmap in magma(i know +Apply Texture)
3)does size of polygonal object affects prtvol density?

As long as you type in the same custom channel name as Output in the first Magma and in an InputChannel node in the second Magma, the data should be passed on.

There isn’t one because of the way Maya was designed. We could not find a way/workaround/hack to evaluate a texture from inside our Magma code. There are a bunch of other things Maya does not let us do, like defining custom shadow map generators for example. Using an Apply Texture before the Magma is the only way to get to the data.

Yes, in two ways.
First, using the same Spacing and other settings on two objects with different sizes will obviously create a different number of particles.
Second, the per-particle Density channel is distributed to the particles according to the space they affect.

So if you use the same Spacing on a box with size 10 and one with size 100, you will get a lot more particles in the latter one, but the per-particle Density channel will be the same.
But if you compensate for the size and change the Spacing for the larger object by increasing it 10 times, the particle created in a larger voxel would receive a much higher Density value because it represents a larger volume.
Let’s say you had a Spacing of 1.0 for the object with size 10. This would produce voxels with size 1x1x1. If only one particle is requested per voxel and no subdivisions are used, the particle will have a Density value of 1.0 (because it represents a voxel with a volume of 1 cubic unit). Now if you pick a mesh with size 100 and increase the Spacing to 10 to produce the same number of particles, each voxel now has a volume of 10x10x10 = 1000 cubic units, and the Density channel of the particle generated in that voxel will be 1000.0! If you would Jitter the particles and request no subdivisions, but 100 random particles per voxel, each particle will have a density of 10.0 (so the sum of all Densities in the voxel would still be 1000.0, or 1 per cubic scene unit.

This is discussed in detail here: … rendering/

thanks bobo

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