P3D v5 PBR Issues...

[Shaun]

My gorund polys PBR don't seem to be reacting to light properly. In the morning the asphalt is illuminated and reflects the sun, but in the evening, after midday they just go dark and stop reflecting light as if the smoothness goes to black. Any ideas what might be up with it?

 

[Shaun]

I see this is because I have rotated some UV islands, and the normal rotation has resulted in the material behaving as if the mesh is facting another direction. How do I stop this please?

 

[Shaun]

This is happening to my markings also, with a normal map engaged they are reflecting light as if the normal is facing the direction the UV is rotated to? This hasn't happened before in PBR that I have used.

 

[Pyscen]

What are you using to create the normal maps, etc?

 

[ronh]

Don't know if this will help , but there is a +y and -y for normal maps.

Question
What is the difference between the OpenGL and DirectX normal format ?

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Explanation
OpenGL and DirectX are two graphic APIs (sets of functions) that programmers use in their application to dialog with the GPU (Graphic Processing Unit). In terms of normal maps, the difference result in how the green channel of a RGB texture should be interpreted. OpenGL expects the first pixel to be at the bottom while DirectX expects it to be at the top. This is often why in various technical discussion it is recommended to try to invert the green channel of a normal map to see if it behave better as it reverses the pixel values (first becomes last). OpenGL can be referred as Y+ (bottom-up) while DirectX is referred as Y- (top-down).
To know which format to use, refer to the target application in which your textures will be used.

 

[Shaun]

I'm using some from normal map generator online and normal map from a pbr set from textures .com

Inverting the green channel seems to not work.

 

[Pyscen]

Can you send a link to this normal map generator.? So we can take a look?

 

[Shaun]

NormalMap-Online

Online NormalMap Generator FREE! Create a Normalmap directly inside your browser! No Uploads required, completely client-based

cpetry.github.io

The normals with a texture.com PBR package asphalt image seem similarly affected.

 

[Pyscen]

The texture was already in a normal map stage? Most PBR Textures do have a normal map included. If that is the case then flipping the Y or green channel usually corrects this. Send the PBR file to me.

 

[Shaun]

Thanks, PM sent.

It's affecting buildings with PBR on it also, it appears fine in Blender.

The more rotated the UV the more it affects the normals.

 

[Shaun]

** Fixed**

[RESOLVED] PBR normal issues - Prepar3D Forums

prepar3d.com

I have found the issue>> The red channel needs to be black and the contents of that need to be put on the alpha channel.

Why can't it just use the standard normal texture?

Thanks.

 

[Shaun]

This is the "Bump" style map that MCX makes "Convert to FS bump", I thought PBR required normal maps, like purple ones not the old style bump maps.

 

[Pyscen]

No. It's not the normal map or bump map that makes it a PBR. It's usually if it has a metallic map or not.

Both the bump and normal maps are purple.

 

[Shaun]

Following the red to alpha (or MCX normal to FS Normal) gives blue, this seems to work fine, and is what was suggested in the thread linked above. Is this wrong?

 

[Pyscen]

Wrong? Explain what you mean? Bluish/purplish pretty much the same once its converted in dds.