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Use Geotiff for Displacement

Posted: Mon Apr 27, 2020 9:17 pm
by Luc
Hi

I've got a a 16000 by 18000 px large geotiff file. If I use this this file for displacement in octane render, no displacement is visible.
I converted the file with gdal to a 16 bit png, but then I got some banding in the displacement. Please see attached image.
Is this happening because of the 16bits, or am I doing something wrong?
Or is there a better way to use a geotiff file for displacement?

Version is: OctaneRender 4.05 (4050000)

Thanks a lot for your help.
displacement.png
displacement_2.png

Re: Use Geotiff for Displacement

Posted: Tue Apr 28, 2020 7:57 am
by bepeg4d
Have you tried to convert it to 32bit?
ciao Beppe

Re: Use Geotiff for Displacement

Posted: Tue Apr 28, 2020 8:42 am
by Luc
Hey, thanks for your reply.

When I try to convert to a 32bit png, gdal gives this error message:

Code: Select all

Warning 6: PNG driver doesn't support data type Float32. Only eight bit (Byte) and sixteen bit (UInt16) bands supported.
If I open the 16bit png in photoshop and simply save it as a 32bit tif, the banding is even worse.
displacement.png

Re: Use Geotiff for Displacement

Posted: Wed Apr 29, 2020 7:31 am
by bepeg4d
You need EXR format for 32bit, PNG is limited to 16bit.

ciao Beppe

Re: Use Geotiff for Displacement

Posted: Wed Apr 29, 2020 8:25 pm
by Luc
Thanks again!

Unfortunately I don't know how I can convert a EXR from a Geotiff file.

I did test the 16Bit PNG heightmap with octane 2020 and texture import type 32Bit. There is no banding visible.
octane2020_texture_displacement_8k_32bit.png
octane2020_texture_displacement_8k_32bit_2.png
If I change the import type to 16Bit, some subtle banding is visible.
octane2020_texture_displacement_8k_16bit.png
In Octane Version 4 with the same settings the banding is still quite strong.
octane4_texture_displacement_8k_32bit.png
Edit: Okay the banding in v4 looks more like the banding in 2020 with import type 16bit. It looked stronger because it was zoomed in.
But why does setting import type to 32bit in 2020 fixes the issue, but not in v4?