JTroy

Just to follow up, I installed the newer graphics card and the flicker is gone so that might be an option for other folks on older Macs.

Well, rats, I was hoping it would be a known thing. I don't want to put a file with a commercial product into a public forum. Is there a way to send it in a more copyright protected way?

I experimented more and tried all of this in R20 rather than R21 since the character was made in R20, and it works just fine. So....what is different about R21 that is making it so that pasting the character into the scene disables the rendering of everything else in the scene?

I bought a rigged character (a cartoon cat with very simple rigging) and when I put it in a scene, nothing else will render. scene 1: I made a test scene with a plane, cube, and light, and the scene renders (both to viewport and to render window.) So, my computer and C4D are fine. Scene 2: If I then add the character (which is about half as tall as a standard cube, so it is not a clipping issue) to scene 1, everything will still render. All is fine so far, but then: Scene 3: when I make a new project file and add the character first, then add the plane, cube, and light. Only the character will render. And it gets even weirder! If I go back to scene 2 where I added the character last, and add a second cube, the second cube will not render but everything else still does. Everything looks fine in the viewport, all the traffic lights are grey, and the default layer is visible. I unrolled all the parts of the character and the only tags are xpresso and various character and weight tags. Nothing to do with rendering. I deleted all the parts that have xpresso and the problem is still there so nothing is hidden in the xpresso tags. There are only a few standard materials and I even tried converting them to PBR using the cineversity script and threw an HDRI rig into the scene to see if it was a material problem, but the behavior did not change. The render settings are the default out of the box ones. The character also has a version that has textures for Octane, so it may have been originally built for that renderer and then converted to use standard materials if that provides any sort of clue. What else can I look for that would be causing this weird problem?

I am on an old mac as well, and R23 is unusable the flicker is so bad. I've also noticed Photoshop starting to lag, and premiere takes forever to open and on and on. But I found a site that specializes in video cards for old towers: MacVidCards and you can search by which MacPro you have and all the cards are pre-flashed to work with a Mac so I am seeing if just upgrading to better and faster GPU will do the trick. It still won't be state of the art, but it should be -way- faster and hopefully give me a few more years before I need to face the expense of a new computer.