Path Tracer ignores normal map?

Development Rendering
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1

Hey everyone,

i noticed that the path tracer in preview 1 doesnt seem to use normal maps correctly, at least not in the same way as the deferred renderer. As you can see in the following images, the identical meshes and materials are shaded differently when using Path Tracing. The normal maps have a visible effect, but there seems to be a misinterpretation regarding tangent/object normal. This is independent of using nanite btw.

Is this a known limitation, or a bug?

The effect is especially visible around the windows.

B1
B11920×666 153 KB

B2
B21920×666 151 KB

B3
B32035×706 364 KB

On a different note:
Still amazed by how closely lumen can match path traced ground truths in many scenarios.

2

It seems this has not been fixed for UE5 final. Did no one else run into this problem? Does anyone know a workaround to properly display the normalmap when using the Path Tracer?

3

I have too noticed the problem, a great example of this is in Spring Landscape. Using the Normal Renderer vs. Path Tracer.

Normal

image
image1920×1080 597 KB

Path Traced

image
image1920×1080 379 KB

The only workaround I found that works is this
image

You’d have to supply your own displacement or heightmap for this to work and plug it into the Normal Map node, for some reason…the path tracer doesn’t ignore this at all…

Example below:

image
image1920×1080 64.1 KB

This is the only workaround i’ve used in plenty of Path Traced renders using UE5. If someone else has a better method. Feel free to suggest.

4

Hi guys same here…when i use normal flatten node, set value more or less then 1 i get strange mesh triangulation distortion with wrong lights and relfections on mesh…have to try the heigh map solution…but seriously epic such a basic stuff to let it work thank you

5

Old thread i know but I get really mixed results with Normal Maps in the path tracer, they do work as least i can seem them having an effect, but it seems quite shader-specific. Did anyone get any updates on the correct way to use them? Im testing in UE 5.3