Sorry for the delay in writing back - we've been looking into this (using another scene that gets slower with repeated renders - but of course we can't confirm it's the same issue as you have reported, since unfortunately we can't access your scene). For our reference, (Internal ID=427033657)
Some questions for you, if you don't mind
- Which version of Cinema 4D, which version of Corona, which OS?
- What are the Corona Team Render settings? Are they default, or did you modify them at all?
- What speed is your internal network, 1GB or 10GB?
- Does the scene have high geometry, e.g. something like grass that isn't using instancing at all, or similar?
We understand you may not have time to do any testing, but here are some tests that would provide useful information for us
- Does the same scene show this slowdown if it is rendered locally, and not using Team Render? Or does the slowdown only occur using Team Render?
- If it is Team Render related, it could be that data is "backing up" on the network, which might explain the bell curve (first renders are fine, as the backlog increases it takes longer to have a frame marked as complete, and at the end that backlog begins to catch up again). Since these are large resolutions, that's not impossible. You could try swapping to "Abritrated (experimental)" which is intended to help with any network congestion. If that alone doesn't help, you could try leaving it set to Arbitrated and increasing both the client update interval and the Maximum size of packet (so that larger packets of data are sent, but less often) - for larger resolutions, packet sizes of 256 or 512 may be useful, and update intervals of 20 or 30s may be useful
- If you have any information on what part takes longer, that would be great, e.g. is the parsing time for the scene getting longer with each render? Or is that staying constant, but the rendering stage is taking longer? This could be seen in the VFB stats tab.
Also, the VFB render stamp (which can be added as a multipass render element in the latest versions of Corona 5, and saved separately by enabling saving of all passes in the C4D save set up) can be used to show parsing time, render time, memory use, number of primitives being rendered, and so on. In case you are able to look into that, here's the render stamp I use in my tests that includes the relevant info, you can copy and paste:
Corona Renderer | Corona Mem %mcp | Corona + C4D Mem %mpp | Parsing Time %ptp | Noise %pe | Time: %pt | Passes: %pp | Primitives: %si | Rays/s: %pr
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If you are able to replicate the issue in a scene that is safe to share with us privately, that would of course be awesome. We appreciate your patience, and any additional information you can give (and if you can do any specific tests, very much appreciated!)
