Lighting and Bump effect on normal maps...

Development Rendering
1

Hey guys…
I have a problem / question about normal maps in UE4… Normal maps need basically good or a lot of light to see the “bumping” effect om them, right?
What about assets which are placed in darker / shadowe regions ? Is there any way to tweak the bump amount up ?

I’m asking cause i have some assets which look great in the “sun” but not really good in “shadow” regions of my map… in fact all the created details by the normal map are gone…

2

Hi,

The “structure” you see on an (otherwise flat) object that is created by a normal map simulates basically a kind of “self shadowing” of the surface.
Little “bumps” cast shadows on the surface. Shadows are a consequence of light interaction, thus lighting is required to have bumpmap details appear.
If you want surface details that are not modeled through these fake shadows, and thus not require lighting to show up, you will need to add this detail on the geometry level. In this case ou cant reduce the polycount with just a normal map.

Cheers,
Klaus

3

Hi,
Thanks for the quick reply, i now that normal maps need the “light” but i thought there is a way to work around with some trick or tweak :slight_smile:
What about a height map? i guess is should produce the needed details even on a flat surface, right?

4

Hi,

A heightmap is not so much different from a normal map. The one can be derived from the other.
A heightmap is just a “grayscale” map that defines a kind of “offset” from the nominal surface, while a normalmap defines a direction for a normal vector.
In this sense, a heightmap is a normalmap where all vectors point “straight up” and the value defines the length.
In both cases, all that this information does is modifiying the received lighting (or its attenuation) in the shading process.

You have to keep uin mind that the heightmap does not really shift the geometry. If a detailed heightmap were supposed to model or shape the geometry, you would need one vertex per textue pixel.

Cheers,
Klaus

5

Ok perfect, many thanx for your help

6

use AO maps those can fake occlusion effect when no direct light applied