Why viewport and render view is different?

[ayushbakshi98]

It's been months that I'm suffering from this issue that should be a few click thing. I tried several methods:
1. Changing displacement attributes
2. Ensuring scale of object and camera is at 1

3. Too many youtube videos and forums

Here's the attached sample file:

https://mega.nz/file/XllmGSyK#3lzeiGcCj3GGN_NZlbq8hc4kTxdi73ypiYR4MRjiN0c

Here's the issue:

It looks like that the plane is offset to the right bottom of its actual position.

Please let me know what I'm doing wrong or if it's a bug.

[LFGFX3D · Accepted solution]

Looks like your displacement zero value is incorrect. Go to your plane shape node and under arnold /displacement you'll see 'scalar zero value.' Adjust it to 0.5 and see if that works.

Arnold needs to know which value is equal 'zero' displacement. That value will be different depending on the bit depth of the displacement file you're using. For example , if you're using a regular 8bit file (eg., JPG) as displacement, the values in the file go from 0 to 1 only. A typical displacement moves points up or down depending on the gray value in the file. So for a 0 to 1 file, 0 is typically not the actual 'No displacement' value. It's actually the max 'down' value. The 'No displacement' value is actually 0.5 and any value below that moves the points down and any value above that moves  the points up. So the scalar zero value needs to be adjusted so that arnold correctly interprets the file and treats 0.5 as 'No displacament' value. 

It is different for high bit depth files (eg 32 bit) as they can store data outside the 0-1 range. So those files will typically store 'No displacament' value as 0 so you don't have to adjust the 'scalar zero value'  in arnold. 

It all depends on the displcement file format your using and how the values are stored. Hope this makes sense 🙂

[ayushbakshi98]

Hi,

Thanks for in depth explanation.

I am using 32 bpc EXR with 0.5 value.

Based on your description, I should try '0'.

I'll try once I get back to my pc.

[ayushbakshi98]

I tried different values. 0, 0.5, 1

I can't get my plane to displace up and down from it's original position in viewport.

For still renders I can afford this absurdity but I like my camera moving which is impossible to set right now.

Here's a screenshot, viewport versus render.

I just want to a get a peaceful render as I'm seeing in viewport. :')

Also, if you've used other tools like blender, C4D etc, is displacement that big of a challenge there too?

[ayushbakshi98]

Okay, I figured it out.

Somehow at some point the height map color profile got set to sRBG instead of RAW.

Value '0' for scalar zero value is working fine for both 16 bpc PNG and 32 bpc and EXR (stair like displacement).

I used painter plugin to set the material and checked the color settings.. today I rechecked and found it to be wrongly set to sRGB.

Other findings,

Using 32 bpc EXR is now giving a stairlike broken displacement with autobump ON and OFF.

16 bpc PNG is giving the best results.