philnolan3d Posted November 17 Share Posted November 17 I'm a little rusty with exporting. I did a 3D scan of a banana for fun. I brought it into 3DC and did retopo, UV, and baked the textures. It looks great in 3DC! So I export, load it into LightWave and it looks good in Modeler, but when I try to render parts of it have bad shading. I narrowed it down to the normal map. Any thoughts on what it could be? Quote Link to comment Share on other sites More sharing options...
Carlosan Posted November 17 Share Posted November 17 look as Y channel inverted... * Gemini answer: (hope this help) When exporting normal maps from 3DCoat for use in LightWave, you typically need to invert the green channel (Y-axis) of the normal map in LightWave's material settings. This is necessary because 3DCoat defaults to a +Y (green up) normal map orientation, while LightWave's normal map implementation often expects a -Y (green down) orientation. Steps for Proper Export and Import In 3DCoat: Export your model (OBJ format is often recommended for compatibility) and the associated normal map texture. 3DCoat's default export settings for normal maps usually work, but be mindful of the +XYZ orientation. In LightWave Layout: Load your exported low-polygon model. Open the Material Editor for the surface. Add a Normal Map node (or equivalent bump node configured for normal mapping). Load your exported normal map image into an Image Editor and connect it to the Normal Map node. In the Normal Map node's properties (or the image node's settings, depending on the LightWave version and workflow), find and enable the option to "Invert Y" or "Flip Green (G) Channel". This corrects the axis difference between the two applications. Ensure the texture image node for the normal map is set to Linear Color Space (or non-color data) to prevent incorrect color correction from being applied, which is standard practice for normal maps in most render engines. By inverting the Y channel, you ensure the normal map correctly describes surface details in LightWave's coordinate system, preventing lighting errors and inverted shading. Quote Link to comment Share on other sites More sharing options...
philnolan3d Posted November 17 Author Share Posted November 17 Thanks a lot. I'll check what songs I used and adjust. 1 Quote Link to comment Share on other sites More sharing options...
philnolan3d Posted November 20 Author Share Posted November 20 So here are the export settings I used. I don't see where to set +Y / -Y. Turning invert Y on or off in LightWave changes the render but it's still not right. It seems like only some UV islands have a flipped normal map. Quote Link to comment Share on other sites More sharing options...
Carlosan Posted November 20 Share Posted November 20 As I know it is ok, LightWave defaults to using OpenGL normal maps. It is ok on Modeler but wrong in Layout ? this is strange... Quote Link to comment Share on other sites More sharing options...
philnolan3d Posted November 20 Author Share Posted November 20 Well you can't see normal maps rendered in Modeler so Layout is the only one relevant. Quote Link to comment Share on other sites More sharing options...
Carlosan Posted November 20 Share Posted November 20 Can you share the expot model to takw a look ? Quote Link to comment Share on other sites More sharing options...
philnolan3d Posted November 21 Author Share Posted November 21 Here is the LWO, color and normal images, and the 3B file. https://www.dropbox.com/scl/fi/mo0qyazoicii2dxdppcd3/banana_scan.zip?rlkey=k2r4nbrjrlatpdsgqkpiy51fs&dl=0 Quote Link to comment Share on other sites More sharing options...
Carlosan Posted November 22 Share Posted November 22 Try exporting without subpatches & turning on Use Source Position I have imported the lwo into Blender, but cant find any issue Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.