Rendering with Render mask clears previous render

I’m trying to fix a big render (20K x 6K) because of some buckets that rendered incorrectly with distributed rendering.

I created a black and white mask (set environment mapping to screen) and put it in the render mask. My settings in system are set to previous render (unchanged), but it keeps clearing the render. What am I doing wrong?

Ok apparently it has something to with the length of the render elements being longer than 64 characters, but that’s just ridiculous. Can this issue be fixed please it’s more than 6!!! years old: Rendering with Region or Render Mask on clears all channels on the Frame Buffer. - Chaos Forums

My paths aren’t that long at all btw, the total amount is 84 characters.

The thing that bothers me the most is, that I’m not even saving any of these render elements (not even the vrimg or the common file), I’m working straight from the VFB.

Changing the path of the render elements to C:/Test/ which makes the longest path 62 characters according to the render element dialog, doesn’t work either.

Does anyone actually use the rendermask? Because I can see this limitation affecting a lot of studios, or does everyone just render to C:/CAM01.vrimg

I don’t use it. I don’t really trust it to give me what I’m expecting 100% of the time. I usually just load a previous render, turn off clear VFB, make region either to a specific area or to the entire VFB to ensure the VFB isn’t cleared, turn off any GI preview passes, and render over the top in the bucket mode and drag the mouse around to where I need updates done…

Lol that’s…poignant actually. I keep forgetting why I never use render mask, to pick it back up a couple of years later, to keep running in the same problem. How do you even get around it? I couldn’t, because even being within the limit, it wouldn’t keep the previous render, so I just rendered the whole thing again.

All in all I lost more than half a day trying to make it work and another day for rendering it out, for something that could’ve been fixed in 10 minutes with a render mask.

Chaos if you’re reading this, please fix this, or provide us with a workaround (if the image is already rendered, so paths were already set up) or at least an explanation why you couldn’t fix it in the last 10 years. Is it a windows limitation?

I keep my paths and file names especially, extremely short to avoid character limits and other nonsense but a 64 character limit feels like an 1980s problem not a 2020s problem.

I don’t believe I saw a scene where this actually happens for all those years, so if you have one - please share it.

which makes the longest path 62 characters according to the render element dialog, doesn’t work either.
Does it work at all for you? I tested the render mask in a simple scene and had no issues. Is this the same scene as in the thread about buckets in DR that you opened?
If yes we will need it for this thread as well.​

Hi Peter I’ll send you a PM with a video link showing the issue. Maybe by what you see you can spot the problem. If not then I’ll upload the entire scene, it’s quite a huge one to pack.

Yes that’s the same one. I haven’t tested in other scenes or with smaller resolutions, but it’s reproducible in this one.

Just uploaded the scene: #258403

For anyone with the same problem at this moment, answer from Vladimir:

It seems the issue is happening when you have loaded the vrimg using the Load image button in the VFB and render with render mask on top of it.
If you render the whole image and after that render the mask without closing 3ds Max it works.​

Hoping for a fix for this one! Thx!

Thanks @Vizioen
There is a workaround. Enable the region render in your VFB and the loaded image will not be cleared.​

Ah ok great thanks, that’s a good hack. Will this be fixed eventually?

Yes - you can download the latest stable nightly and the fix should be there :slight_smile:

Awesome, thanks for the speed guys!