Chaos Scatter and Cmaera Projections

[Joelaff]

It seems that Camera Projections don't work with Chaos Scatter-- either WSM or object space.

I guess I should try Forest, but are there any workarounds? I'd like to render with Standalone, so Forest becomes very inefficient.

Would be a great feature to have, but I am sure it is challenging technically, though could in theory still be done at a clone level, without loading everything into RAM.

[vladimir_krastev]

Hi, thanks for posting. Could you explain a bit further what are you trying to do?
Are you talking about Forest Pack's Look-At functionality where you can orient your objects towards the camera like in the gif below?

[Joelaff]

Sorry, I may not have been very clear. I was trying to add a Camera Map WSM modifier to a Chaos Scatter object, and this does not work. I would like to be able to use a camera to create UVs for the entire scatter object. This results can be achieved by converting the Scatter to Max geometry and them applying the Camera Map WSM modifier, but obviously this makes for big files, and no editability like with a Chaos Scatter.

[vladimir_krastev]

We will discuss if this is even possible and get back to you.

[vladimir_krastev]

Hi, could you please share a bit more details about your project? We are curious to know what kind of workflow could need or benefit from such a feature. If you could send us an example of your work that will be best. In case your project is confidential or you don't want to reveal it to a wide audience, please use the support contact form. Please add a link to this thread in your message to support.

[Joelaff]

There are numerous potential cases for such effects. In this case it is a stadium full of seats where the seats need imagery on them. The imagery needs to be projected from the position of a camera.

Imagine any classic camera map setup for VFX. For instance make a landscape covered with small rocks (scattered) and then project a matte painting on that so you can add a camera move to the matte painting with parallax.

The possibilities are endless. Camera mapping has been a big part of VFX since at least the 1990s when we were doing it in Electric Image. There just wasn’t much scattering available then.

Nowadays we do more and more camera mapping in compositing apps that support 3d, but they lack scattering. So being able to combine the two techniques is of great value.

[vladimir_krastev]

Hi again. We managed to find two possible workarounds to this.

First one is by using the Camera Map Per Pixel in the instance's material instead of a modifier over the Scatter.
The draw back is that you will need to edit your materials.


A second workaround can be achieved by using the VRayDecal object. The Decal can be aligned and linked to the camera to project in the same direction.
The drawback is that our skater has to be within the decal's gizmo boundaries. Depending on the camera movement this may cause difficulties.

[Joelaff]

Thanks for this. I thought I had tried Camera Map Per pixel, but I guess not. I know I have run into lots of problems and incompatibilities with it in the past. But could be useful here.

The decal is a neat trick! I guess that is a flat (planar) projection, rather than a point source projection like the camera, though. Still useful for a lot of things.