SteamRoller Unwraps Some, But Some Not...

I am using the SteamRoller script available for download over at ScriptSpot and it is both a life AND time saver! Highly recommended.

I am having some issues with flattened and uwrapped channel info not showing up in UE4. Some meshes are just fine and I see the flattened and unrapped lightmap information in UE4.12.5 just fine. On the problem meshes, I see no flattened and uwrapped channel info even though I see this info in 3ds Max. In Max, diffuse maps/materials are on channel 1 (0 in UE4). When I use the SteamRoller script, flattened and uwrapped information is on channel 3 (2 in UE4) in the Max dialog. This works just fine for some 3d models without a hitch. On the problem meshes, there is no flattened and unwrapped information on channel 2 (3 in Max/SteamRoller) or any UV information whatsoever. Why does this work on some meshes and not on others? Some of the 3d models are not “dumbed down” - saved as meshes or editable polys in Max. Does this affect what the script is doing? I thought exporting to FBX removes any information that is in the modifier stack on models still being modified.

Please see attached screenshots.

Your help and the help of others is greatly appreciated in advance. THX

Art in Seattle

You need to have your lightmap UV’s set to be the second UV channel–I don’t know that you can have an empty UV channel between two others in UE4, that might be an issue. Also note that UE4 by default will try to generate lightmap UV’s to a new channel, so if you have them already then disable that and it will automatically set the second channel as the lightmap channel.

Also, the automatic flatten UV’s feature does not work very well, you can see in the UV’s there that there’s some very thin parts which are going to end up thinner than a pixel and you also don’t have enough space between each piece which means it’s going to bleed across the edges.

Hey, this is the dev that made Steamroller on Scriptspot. Sorry to necro an old post, but I thought I’d let any interested parties know that I recently went back and updated the script to fix some long-standing bugs. If this issue still happens or if anyone runs into any similar issues, please let me know.