Author Topic: Render Overlap number ranges (for crops)  (Read 2111 times)

Offline moodflow

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Render Overlap number ranges (for crops)
« on: September 10, 2007, 12:44:48 AM »
Well I put together some "hard" number ranges for rendering a scene via the cropping method.  This will only interest those who like to render larger scenes in slices on multiple machines and/or render in sessions so the PC isn't tied up the entire render.

Reason:  Due to the GI issue, each image still needs to overlap each other, then be blended and stitched in a 3rd party graphics app.   I arbitrarily picked 12% as a good overlap, as anything smaller "may" have some GI artifacts spilling over, and anything bigger is wasted render time.  I also decided to slice the entire scene into 4 individual images (since I have 4 cores available).  With that, there will be 3 areas of overlap and 4 individual images which overlap by 12%.

For a 4 slice scene, and 12% overlap, the number ranges so they are all equal slices are: 
0.00-0.34  - 1st slice
0.22-0.56  - 2nd slice
0.44-0.78 - 3rd slice
0.66-1.00 - 4th slice

But why all the fuss?  Initially, it will seem simple - just render the image in quarters with and overlap on each side of the quarter mark.  But this is not efficient, as the two 'end' renders will render less than the two images in the middle, since they didn't have to render an overlap on one of their sides!  They will finish first and sit idle while the two inner slices are having to render a bit more.   This means additional render time.   

(Hopefully, I haven't lost anyone by now!)

Anyway, the numbers above are what each slice width should be so each is the same size, with 3 areas of 12% overlap (each image width is 34%).  With this, all of the renders will render the same amount of scene, and efficiency is maximized. 
« Last Edit: September 14, 2007, 12:22:21 AM by moodflow »
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