Displacement texture different in Preview vs. Render

Support Materials and Textures
1

Hopefully this is the right forum to find help, it’s to do with displacement textures . . .

My render for a test snow scene has started to differ radically from the preview in 3D view.

It’s frustrating, because i can’t compose anything accurately.

I feel i’ve likely made an errant shortcut key press

You can see here what i mean. The snow hills are a displacement modifier based on some noise texture. the left is a the a screengrab through the camera’s view in 3D view, the right is the rendered output. Even the snowball and stand-in ice cube change, so I don’t think it’s object dependent.

I feel like this started happening as i was building the scene, not from the very beginning.

direct compare.jpg1036×463 159 KB

Here’s a screengrab of my workspace, is there anything else i can show you to help narrow it down?

screengrab of preview.jpg1920×1044 478 KB

2

Check the number of preview vs render levels on your sub surf modifier.
It looks like the displacement map does not have enough geometry to work with in the preview so you are only seeing the finer detail in the render.

3

Is it just because the noise pattern is generated randomly from scratch each time it’s “looked at” or referenced? I guess i just now noticed that if you tab between object and edit mode, the displacement is applied differently each time…

Subsurf Render and Preview are set the same. That was an original thought of mine as well.

4

and obviously if i apply the displacement above the subsurf it gets applied as seen in the preview and the render naturally matches.

5

Jump over to Blender Internal then and make your noise pattern from a cloud texture.

6

Good point. when noise is switched to a cloud texture and the settings tweaked to give similar little snow hills the results are as consistent as expected. I don’t quite like the nature of hte hills as much, but I can fall back on the noise + applying the displacement for situations where i need that look instead of clouds (among other options). Sweet! Another tool for the toolbox :smiley:

7

I use the cloud texture often for noise.
Don’t forget to adjust the brightness and contrast of the clouds to get sharper or softer division of color.

8

Indeed, i’ve been doing that in photoshop forever :wink:

9

Don’t use the displacement socket on Cycles materials. It’s an broken/unfinished feature that will not be fixed until OpenSubdiv 3.0 is released. Currently the Displace modifier is the only reliable way to do displacements with Cycles.

10

Curious in what way. It did exactly what i expected it to here. You mean that it doesn’t affect geometry, just fakes texture using modified normals?

aka, use the Bump node instead?

11

Using a procedural texture kiiind of works, there will still be non-watertight dicing in certain cases. Image textures don’t work at all. If all you’re going for is bump, use the per-material normal input with a bump/normal map node.