How to specify in command line list of tiles or part of the screen to be rendered?

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1

Hello everyone!

I am still new in Cycles development and want to figure out one thing:

  • if I do not want to render all screen, but just a small part of it - how to specify it?

As I understand Cycles split the screen into tiles and render it separately - so if I specify some list of tiles - I will be able to render some specific part of the screen.
But in cycles binary command line I see params to specify tile width/height, samples count, but not tiles list to be rendered.

Could you please help me to figure out how to make rendering just some specific part of the screen?

2

Based on the answer here the following script can be used to specify a region of the image to render (called “border render” in Blender):

# border_render.py
# $ blender -b <file.blend> -P border_render.py -- <minx> <maxx> <miny> <maxy>
import bpy
import sys
argv = sys.argv
argv = argv[argv.index("--") + 1:]

scn = bpy.context.scene

# setup the render border
scn.render.use_border = True
scn.render.border_min_x = float(argv[0])
scn.render.border_max_x = float(argv[1])
scn.render.border_min_y = float(argv[2])
scn.render.border_max_y = float(argv[3])

# render a still frame
scn.render.filepath = '//out.png'
bpy.ops.render.render(write_still=True)

For example, call it with

blender -b file.blend -P border_render.py -- 0.1 0.8 0.1 0.3

Here, the min max values are all in range [0,1] and specify the area of the image to render. Note that Y=0 is the bottom of the image.

This will still output an image in the full resolution, it does not crop to the region specified.

1 Like
3

Thanks, Paul…
I will try.
But maybe it’s possible to make rendering without Blender but via Cycles renderer only? :slight_smile:

4

Ah, you’re working directly with the Cycles code. Then I think you should be able to set the same values on Cycles’ Camera class, instance variable border (but that’s from looking at the source just now, haven’t tried it).

5

In ideal case, I want not to change code of Cycles renderer, but just to use power of existing command line binary without launching Blender :slight_smile:

But seems that here is really code should be improved to be ready to work with specific tiles or screen part…

It will be much harder to improve C++ code than to improve Python scripts. But ok… let’s try :slight_smile:
(but I still hope that there exists easier way :slight_smile: )