Hello,
Here is a minor bug with the new PBR materials in Sketchup Pro 2025. When we select an image for the occlusion texture, it is internally converted to grayscale—logical enough, as the occlusion is just a number between 0 and 1, corresponding to a shade of gray from black to white. It seems from my measurements that the conversion is done using the formula (r, g, b) → 0.11*r + 0.59*g + 0.30*b (tested on PC). If I’m correct, this is clearly a minor bug, as the expected color-to-grayscale conversion formula is the same but with the factors for r and b swapped. In other words, there is a RGB-vs-BGR issue.
Armin Rigo