And again the mysterious Houdini interface.

Two copies of Houdini, one with OpenGl, the other with Vulkan.

1. Screenshot with tori with the same matcap. The same gamma settings, all by default. The picture is strikingly different. Why? Which of them is correct?

2. File from the content library Texture_mask_paint. Three screenshots, because I had to turn off the lamps.

1 screenshot - both areal lights are disabled.

Why does Vulkan look so bad? The tiles are all torn, as if the resolution is 4 times smaller. Does Vulkan need any other settings? I searched, but couldn't find any.

2 and the third screenshot - I turn on areal light one by one.

White areal light has no noticeable effect. But turning on the yellow sphere destroys OpenGl, but has almost no effect on Vulkan, gives a barely noticeable yellow glare. The difference is simply enormous.

Total -
1) matcap looks good in Vulkan (but crashes Houdini when resetting with matcap), but looks bad in OpenGl.
2) COP - looks good in OpenGl and looks terrible in Vulkan.
3) Lamps - overexposure in OpenGl, and good in Vulkan, much closer to the brightness in Karma.

What can I say? Houdini's amazing ability to make problems everywhere...

Although lamps are still more important and Vulkan wins overall. Probably.

Vulkan should be taken as correct from 20.5 onward. Development on OpenGL has ceased, and we're only doing critical bug fixes on it until we remove it. GL will live on for at least one more major version.

Area lights were redone in 20.5 for Vulkan so that they match Karma much more closely, but the GL version remained untouched. Also, if GL is not in high quality lighting mode, area lighting falls back to a simple point light representation, which can be very different.

As for displacement, Vulkan isn't as aggressively subdividing the geometry as GL is for performance reasons. You can control the displacement LOD in the Material tab (the field beside the displacement toggle).

Oh, thanks, malexander! It's always good to get some clarification on where we're going.