0

I am using Blender to create a 3D model of a location/building with data points demonstrating the data values through their colour. Red is negative, white is zero and, blue is positive. I imported the data as a point cloud with the associated rgb values calculated from a colour ramp in python and used geometry nodes to create the visible points. However, when I render the scene (Engine = Cycles), the colours are altered with the deepest red changing to a magenta and pinks becoming a lighter colour closer to white. Data values looking closer to 0 is an issue and would change the interpretation of the data.

I have seen a similar question here: Desaturated red when rendered but the answer seemed to suggest the changed colours are correct for a "physically plausible rendering scenario". As the rendered data points are not 'real' objects in the world I am not concerned with their appearance being plausible. I just need a method of retaining their 3D look and intended colour as described by the divergent RdBu colourmap of matplotlib: https://matplotlib.org/stable/tutorials/colors/colormaps.html, everything visible besides the points is a mesh created a process of importing a portion of Google Maps 3D view. I hoped any solution would involve changing the points rendering but keeping the look of the landscape the same but I do not know if it is possible.

This image below uses 'Standard' in the render 'Colour Management' but similar issues are found for 'Filmic' with a greater washed out appearance. enter image description here 'Raw' is shown below and does not achieve what is needed either. enter image description here

Alex
  • 1
  • You probably should use an emission shader on light path -> camera – Allen Simpson Aug 26 '22 at 18:54
  • @AllenSimpson, I am unsure if I used an emission shader in the way you suggested as I don't understand how/where it relates to camera. But I did find an emission shader for the rendered data points material keeps the colour better but only when using 'Raw' on colour management. However, this leaves me with the background looking like the bottom image of my post. If there was a way to combine the rendered background in 'Standard' and points in 'Raw', that'd be great but I believe this is not possible. – Alex Aug 30 '22 at 11:36
  • You could render two scenes, balls and background, and combine them in the compositor. I'm not sure if you can render them with different color management (CM) at the same time. But you could do 2 renders, like save the output in the compositor, change CM, render the other scene, load the first render and comibine it in the compositor. – Blunder Aug 30 '22 at 13:23

0 Answers0