Steffen Dünner

Linux (Mint) user here with latest nVidia drivers and latest production build of H20.0.688 but I can reproduce the very same issue on a totally different machine with Win11 and latest nVidia drivers:

Every time I double-click an RBD Bullet Solver to enter the realm of DOP forces and start adding e.g. a POP force and toggle the brown output flag the viewport switches to "Smooth Wire Shaded" mode.

If I now go back to Geometry level and e.g. try to switch the RBD Bullet Solver to display the Proxy Geometry or Constraints (with the rather new and awesome 1,2,3 key shortcuts) the viewport doesn't update and keeps displaying the same geometry.
I can navigate without problems but the geometry that was visible back in DOP forces mode is somehow stuck in the graphics card's memory so to say. I can even disable the blue display flag at Objects level but the geometry stays visible.

Labs "Reset Viewport" or restarting Houdini helps, but it is quite annoying.

jsmack
this is the result with Cycles. It seems to be losing a lot of energy when it stacks up in depth, even though I have indirect unclamped and 24 bounces. is it just fast because it's cheating and wrong? I would think even 4096 wrong samples would take longer than 1024 good ones.

Just in case: In Cycles you can up the "Min Transparent Bounces" to make sure Russian Roulette doesn't terminate transparent rays too early. Maybe it helps. Energy conservation / preservation shouldn't be a problem in latest Blender 4.x any more.

Just downloaded the 19.5.407 and Vellum is working with OpenCL again (Linux, nVidia drivers 520.61.05).