did you know that you can also emit particles from just the alpha channel? All we need to do is to convert the alpha from a 2D image into a 3D point cloud. But how do we achieve that? We can use an STMap to set the X and Y coordinates and then manually set the Z value to 0. Now you have a custom position pass for your 2D image. Just add a PositionToPoints node, connect your alpha and the custom P pass we created, and now you have a point cloud representing your alpha channel in 3D space. To transform your point cloud, simply add a TransformGeo node, and that’s it! You can experiment with this technique to create a variety of cool effects. To avoid the headache, I’ve created this Gizmo that does it all for you.
HM_AlphaToPointcloud
Updated: 19 June 2025
Author: Hosny
Compatible Nuke versions: 11.0 or later
Compatibility:
did you know that you can also emit particles from just the alpha channel? All we need to do is to convert the alpha from a 2D image into a 3D point cloud. But how do we achieve that? We can use an STMap to set the X and Y coordinates and then manually set the Z value to 0. Now you have a custom position pass for your 2D image. Just add a PositionToPoints node, connect your alpha and the custom P pass we created, and now you have a point cloud representing your alpha channel in 3D space. To transform your point cloud, simply add a TransformGeo node, and that’s it! You can experiment with this technique to create a variety of cool effects. To avoid the headache, I’ve created this Gizmo that does it all for you.