Rendering Autodesk Point Cloud - Colors & Exposure.

[SnipeyX]

Is there any way to manipulate the colors of an Autodesk Point Cloud object set to "True Color"?

I still find myself still bouncing back and forth between using Krakatoa to render lidar data versus loading Recap files via the Autodesk Point Cloud object and rendering directly in Vray. Typically I prefer Krakatoa's speed and ability to manipulate the data and just comp it with the vray render, but today I needed to render a point cloud reflected on the ground. This led me back to the Point Cloud object and trying to render it directly in Vray, but results were horrible. I'll assume the implementation of the Point Cloud object is to blame, I don't understand quite how it works or what sort of geometry vray treats it as. Ignoring the fact that it produced ridiculous noise all over the image, what I was more interested in for now was that I ran into the situation where I am using the Physical Camera & Exposure in 2016, but seemingly had no way to control the colors of the point cloud object. The gamma always seems to be opposite of what I want in the Point Cloud and in this case due to my exposure settings the point cloud was blown out white (where the rest of my scene was lit as I intended.) Initially I went to the Autodesk Point Cloud material and tried messing with the settings there, "Color multiplier" seemed like exactly what I needed, except I found it had zero effect on the render, and interestingly I went so far as to completely remove the material from the Point Cloud object and it still rendered the same "true color" as seen in viewport. If I tried to render it with a vray material, it went all black. I guessed that perhaps the color data was stored in a vertex channel so I put a vertex color map into the diffuse and that didn't get me any results either, at which point I gave up and went back to Krakatoa.

I started looking into the 'render the pointcloud as a krakatoa atmospheric' technique Bobo mentions here so that it can be used as reflection natively in vray, but that got quite complex to load. The voxel grid was so slow to deal with I don't know that I'd be able to optimize it down far enough to realistically use for anything that took less than hours per frame.

Anyone have any insight?

[elivnA]

Hey, sorry to dig up an old thread, but i'm having the same problem. Is there any fix or workaround for this?

[SnipeyX]

Obviously I never got any feedback here, and I don't think I ever dug into it further, I still just use Krakatoa when I need to render points.

[elivnA]

unfortunately I don't have access to Krakatoa.. guess we will fix it in post :P

[asen.atanasov]

Hi,

the color multiplier of the Autodesk Point Cloud material is working since March. Which build are you using?
Point clouds are rendered as disks which always face the camera. Usually, the color data come from scanners and it is already shaded. In these cases Autodesk Point Cloud material or no material is used. If you want V-Ray to shade point clouds as standard particle systems, you need to assign some of V-Ray materials. What exactly do you expect?

Best regards,
Asen

[elivnA]

When I load an Autodesk pointcloud object in max 2016 it looks like this in the viewport:



but when i render with vray, it looks like this:



I'm using the default autodesk pointcloud material, and i want the colours to look like they are in the viewport. I'm not using any lighting in the scene. The colour multiplier does not make a difference (0, 1 or higher)

[elivnA]

Oh sorry, and i'm using Vray 3.50.04 with 3dsmax 2016 SP4

[SnipeyX]

what if you disable gamma in max preferences?

[elivnA]

That does not seem to make much of a difference.

[michael_erickson1]

I am wondering about the outcome on this?  We render PC in may projects and are looking to switching to V-Ray, but we need to have some control of how the PC renders. Did you find a solution or workaround?

[matanov]

Yes, we've added a texture for this - https://docs.chaosgroup.com/display/...ointCloudColor

You can use it as a regular color texture that reads the info from the set color channel in the point cloud and do whatever corrections you want through the Output or Color Correction map.