Displacement map shading behavior

[robcat2075]

These two coins have displacement maps on them with similar settings. Both maps attempt to create details raised above the main surface.

 

The top one with the simple bumps on it shades as expected for the light coming from above the camera's left shoulder. The more complex one, with the monkey image, has a varied result with different details seeming to be lit from different directions.

 

 

 

Does anyone know why?

 

DisplacementTest.zip

[Walter Baker]

Sorry Rob I can't help, I haven't figured out what a displacement map is yet. LOL

[NancyGormezano]

Hmmm...I noticed that if I applied the decal straight instead - ie, not reversed scale like you had done, that it would display correctly - I would say reverse your image in photoshop. Originally I thought perhaps because the hole hadn't been closed (so I closed it) - but it seems more related to reversing the scale (-1390%, 1390%). I also added a bump to the displacement.

myCoin.mdl

[robcat2075]

Thanks, Nancy! I wonder what goes on internally that makes the reversed map come out differently.

 

I also added a bump to the displacement.

 

I don't think that gets you anything since Displacement relies on bump-style shading for its shading (shhh, dont' tell anyone it's a trick!). It uses the displacement map twice, once to elevate the surface and once to give it a shaded appearance.

[NancyGormezano]

I don't think that gets you anything since Displacement relies on bump-style shading for its shading (shhh, dont' tell anyone it's a trick!). It uses the displacement map twice, once to elevate the surface and once to give it a shaded appearance.

 

It can change/augment the effect if you play with different %'s for the bump - I made this one 1000% versus previous was 100%. Just More tweaky for deaky.

[R Reynolds]

Careful how you mirror normal maps, they are very orientation specific. I modeled two hemispheres, convex on the left, concave on the right, and applied the normal material to both. Notice that to make the left map look like the right, you'd have to mirror it in both X and Y. Flipping a normal map in a paint program, in only one axis, gives unexpected results.