Blending between pointclouds

Hello everyone,
besides a crossfade between two pointfilein-TOPs, which ways can I use to do a directional blending? For example to erode the cloud from right to left and rebuild the next one from the right? I tried a feedback (+ math channel mask on Red and add-TOP) which is only visible while blending (trigger) - doesn’t work very well … (screenshot)
And how about starting from an empty space to build the first cloud from nothing (e.g. from the right again)? I tried to blend from a constant-TOP with (0,0,0) but then the first cloud is only scaled up.
I would be so happy about some advices!

I’m not entirely clear on the effect you’re going for, but you may want to look at the pointField or pointWeight components in the PointClouds section of the palette. Both of these components can generate a weight map based on a point’s position which you can then use to fade or animate the cloud to do things like fade or blend from left to right.

Hope that helps.

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Yes the pointField COMP in the palette is based on the more elaborate examples in this Community Post: Point Field COMP | Derivative

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Also, poorly documented, sorry, is the Point Transform TOP’s second input, which applies per-point transform based on weights in the second input. a 0 weight is no transform, a 1 weight is full transform.

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Hi @derthiemo,

from a technical standpoint for understanding the idea you can think of it as selecting pixels that are in a certain value range on both pointclouds. For crossfading in a directional manner you can make use of the Threshold TOP here with the color channels r, g, and b as the position and alpha as the active channel: The result of the Threshold on each pointcloud is used as the respective alpha channel on the pointclouds via a Reorder TOP.

So the key is not to composite the 2 pointclouds ontop of each other but rather rendering both of them with the alpha channel being used in the Active Parameter on the Instancing Page of the Geometry COMP.


directionalFade.tox (14.0 KB)



Smart & lean. P

I would still explore the Point Field for the heck of it, I used it before and it is pretty rich in terms of possibilities. P

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Thanks a lot! Honestly I first need to invest more time to understand these components and see how I can adapt them to my project …

Oha! Thank you so much @snaut
How can I create a soft fade rather than this hard line? It should create some wind association (erode to one side and rebuild from the other). I tried to combine it with a pointfiletransform, so the points are blown away.
I need to blend between six .ply files. I guess I need to build a little system of chops that the threshold and layout TOPs always get the right input? Because now I can no longer use a crossfade that chooses between two switches, right?