Render Region other than a Sqaure

Is it possible to render a region that is not a square.

For instance I am trying to render a series of images that are very high resolution with a square aspect ratio. Lets say 3000 by 3000 for each.. However I only need about half of those pixels. Specifically if you draw a triangle with 2 points touching the bottom corners of the frame and the third touches the middle of the top of the frame, that is the area that is required.

As far as I can tell the only way to accomplish this rendering of the area that is required is to render the entire image, so each render has to calculate and render twice what is needed. Which has to be rendered 8 times per frame, and about 17,000 frames.. So I would rather not have to double that render load.

I was hoping there is essentially a mask you can put into the rendered area that will cut off any calculation and rendering of certain areas of the screen, that would be perfect. But I do not see anything like that.

Any ideas would be greatly appreciated.

Thank you

I’m not quite sure what you mean; you can set a region or crop render to whatever rectangle area you want. A blowup render will be constrained to the aspect of your final output, but region and crop modes should be fine.

Best regards,
Vlado

I think he just confused the terms “square” and “rectangle”… as far as I understand, he’s asking for non-rectangular render regions.

only equiangular quadrilateral is possible - no random shapes. I guess it would be useful to have the ability to ‘mask’ areas to render for future release? could be really useful.

Thank you Deflix.

That is exactly what I am referring to.

Some kind of masking ability (other than a rectangular box) detailing what is being render to limit calculations would a great addition to Vray.

So you would use black&white image to tell V-Ray where to render, is that what you mean?

Best regards,
Vlado

Essential. Yes exactly.

That would be a very useful feature.
For now just create an object and link it to the front of your camera, creating a custom matte box.
Apply a black material and make it a vray matte object that ignores lights and GI.
Done.

Thanks raven,

That’s worth a shot… But will be a bit cumbersome with stereoscopic renders
But otherwise great idea.

Thanks.

Create the first one, place it where you need it.
Then align its pivot point to that cameras pivot.
Clone then align clone to the second camera using pivot points.
The real trick I guess with stereo (I’ve only toyed with stereo, never done any production), is that it will need to be pretty close to the camera I think.

Sort of like the Priority Map in Brazil R/S:

It’s a black and white image, where white is the most prio and black is the least.

But isn’t it a bit cumbersome to switch programs just to choose a render region? How about a normal selection lasso in the VFB? (ideally with “vertices” that can be moved after drawing it, like when you’re scrubbing through the animation and see, that you need to make the mask bigger here and there, and you don’t have to redraw it completely, just move some vertices)

I of course meant that Chaosgroup could implement a similar solution.

There was an request to support multiple render regions in VFB. Is that going to work for you?

multiple region and/or b&w map to define render areas would be awesome !!!

+1 yes that woul dbe great

Or perhaps an object ID region would be best?

An Object ID region alone wouldn’t be enough though… sometimes you need just a bit of the scene around the object as well (for shadows or reflections), so just the ObID wouldn’t cut it.

This would be a perfect solution. I’ve wished for this exact feature countless times when need to re-render a small, non-rectangular part of the final render.

Imagine a scenario where a small part of your animation needs re-rendering on every frame; being able to keyframe those points throughout the animation… Now that would be something! I guess very hard to implement though.