I’m having Major Issues with Unreal 4.20/4.20.1, Datasmith 4.20.0 and 3dsmax Datasmith plugin 4.20.
when Exiting Unreal for the first time after Importing a Datasmith scene from max the Materials and Lightmass become corrupt (nodes inside a lot of materials become disconnected by themselves, Lightmass becomes a Picasso painting and so on).
I’ve made a 7 Min Video Showcasing the exact problem, Please take the time to view it before responding because it will save us a lot of questions.
THANKS! VIDEO LINK - https://www.youtube.com/watch?v=EgH03ilju3I&t=22s
I have exactly the same problem : when I save my Datasmith project in 4.20.2, close it and reopen it lightmaps are broken. It’s not Vray material related because I don’t use them. Any clue about this issue?
Hi JuliusD, I had the same problem with the disconnecting textures and it was driving me crazy! I couldn’t find a fix for that, but for the problem you have with the lightmap I could. What I did was delete all the meshes that had lightmap problems, and in 3Ds max I created an Unwrap UVW modifier for channel 2 (leaving my texture mapping intact) and then flattened it. Then I re-imported this meshed via Datasamith, and in the **Static Mesh Build Settings I **used the new UV (in my case 1, as 0 is the texture one) as the source lightmap index and 3 (the UVs automatically created by UE) as the destination lightmap index. I also set 3 as the lightmap coordinate index.
I also have similar problems with the lightmap of the object. I edited the faulty objects in 3Ds Max manually (Unwrap Flatern with chanel 2). I tried importing into UE 4 failed objects after editing with 3 versions:
Object at first error (only imported with DataSmith).
Give the object Unwrap Flatern in 3Ds max with chanel 2. then import it using Data Smith.
Same as object 2 but basic import of UE4.
1 and 2: + Source Lightmap Index: 1
+ Destination Lightmap Index and Coordinate index: 2 (Uv map created by tick Generate Lightmaps UVs)
+ UV chanel 0: Uv map is like unwrap chanel 2 from 3DsMax
3: + Only unique UV chanel 0. Also with Log “has degenerated tangent bases which will result in incorrect shading …”. fix this error by adding a unwrap chanel 1 channel to the object in max, I also don’t understand the reason for this error !?
Source Lightmap Index: 0
Destination Lightmap Index and Coordinate index: 1
Uv chanel 0 opposite to chanel 1
1 and 2: + Source Lightmap Index (SLI): I tried on 2 objects, Source index is always the channel with overlapping UV.
Why DataSmith changed from channel 0 to channel 1 and its effect …!? If I change SLI to chanel 0, will there be any changes? I can build to see the results and I want to understand why. Looking forward to receiving sharing, thanks
This issue is still happening for me in 4.22.3. I exit unreal and reopen it and some assets’ lightmaps get corrupted like shown in the video. Is there something i can do on my end to solve it other that regenerating the UVs for each asset?