Image size in render region vs render full

There are times when I would like to render just a portion of an image, because a slight modification or failure.
Buuut, when I tried using the render region, I discovered that I couldn’t patch the original image because they didn´t have the same image size.
Am I missing something? Is it an overly dirty solution?

Hi arquitextonica,
After you set your image size in the vray settings -> Render Output > Dimensions everything should work fine (on pixel-level), although you might experience slight change of brightness due to a different amount of light reflected.

Doesn´t work for me.
Images are resized by the forum system but I guess they are proportional.


Both images have totally different pixel size and aspect ratio. Are you able to render both of them in 1920x1080?

Would you care to read this section of official documentation if it solves your problem?

Also I would suggest to try working with new file - you might have accidentally changed things.


As said before, process is as follows:

  • Build cube matrix
  • Assign renderer
  • Assign output size
  • Render full > Size is correct
  • Render region (without changing anything, just right click on “R” icon) > Size is incorrect.

VfR 3 or 2?

Version 2

I use my own render tool toolbar and there I use the command _visRenderBlowup. You could try this way.

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If you’re sure it’s not your fault, try reinstalling V-Ray. This is not a standard behavior.

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An other method: draw the region section per frame buffer tool and press render.

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Works like a charm! Thanks!