I would very much like to have an option, so that the opacity of Gaussian Splats can be controlled by a shader like Corona Distance. Why is this important?
Let’s imagine a real world example with the following task: Exterior render of a house and its garden. For the surrounding you scanned the real location and created Gaussian Splats. You now have the building and garden as real 3D objects and the Splats for the surrounding. But how can you nicely blend the real 3D geometry and the Gaussian splats together, so that it looks clean without a “border”?
Let’s say a part of the garden is rendered and a part of the garden is scanned. We would need much control of the transition, otherwise we will end with a clearly visible border, which doesn’t look good.
Right now I would have to do two renders, one without the Gaussian Splats and one with only the splats and then blend it smoothly in post. Because right now, there is no way to make a smooth transition from Splats to 3D objects.
I think, this could be done easier. If the Splats would work with the distance shader (or any other options that let us blend the Splats), we could have much more precise blend option, without having to deal with it in post.
It could be used for other situations too. Let’s say we have a HDRI for the background, Splats for the midground and real geometry for the foreground. How do you blend the Splats (midground) and HDRI (background)? Distance shader could be helpful in this case too.
You know what would be even better? If we would have the opportunity to blend it from both sides, the Splats and the 3D geometry.
Let’s take the example from above: We have the surrounding scanned and modelled the building and new garden. We scattered grass, flowers, and bushes. So we end up with grass etc that are real scattered 3D objects, and we have grass etc from the Splats. We now want to blend the 10 000s of scattered objects with the Splats.
With the feature request from above we would be able to control the opacity of the Splats. But what about the opacity of the 3D objects, in this case all the scattered grass etc? It would be good if we could also blend the opacity of the 3D objects using Distance Shader. This is already possible - but only in the opacity channel of the material. But when we have a scenario like this, with many different assets (and materials), it would be a pain to modify every material with a distance shader.
So my 2. feature request is this: Opacity in the Corona Compositing Tag. Instead of modifying 10s of materials, we could just create a Compositing Tag, add a Distance Shader to the Opacity channel, and add the Tag to the terrain and scatters. That way we could very fast and precise control of the blending without ever needing to go elsewhere.
This two feature request would play nicely together
Clipping mask for GSplats makes perfect sense and it will be reported as feature request.
In the meantime, letting you know that you can use CoronaSlicerMtl to cut off, although sharply, parts of the GSplat.
As for compositing tag and opacity - that sounds more like a compositing thing which is better done in a dedicated application (e.g. after effects). The closest thing to that which comes to my mind is a distance based effect opacity for SlicerMtl - it cuts with some opacity falloff from the slicing volume.
