Need help with Pepakura, weird seam line/edge issue

[LeastFamousStev]

Hey 405th, has anyone seen this before? I get weird seam lines/edges in Pepakura after bringing in models from Blender, which makes my unfolds janky, and I don't know why. Any help or insight is greatly appreciated!

Here was my process to get to this point:
- downloaded a mix of 3D files from Thingiverse and also from The Armory here (thank you Fangs, ODCA, etc for making that thread possible!)
- exported the Pepakura unfolds into OBJs (had to buy a license for that, but no biggie)
- imported files into Blender, including a 3D scan of my body for reference when scaling parts
- after scaling was done, I decimated some of the higher-res models to lower the poly count and make it easier for Pepakura to process them
- exported parts individually as OBJs (MK7 helmet, chest piece/cuirass, upper arm, shoulder/pauldron, etc etc)
- imported OBJs into Pepakura, and began unfolding

Some parts seem easier to unfold than others, and in the case of this shoulder pad/pauldron here I had to omit a portion of the polys in the unfolded pattern (I'm thinking this is a common thing to do). I've also tried merging edges in Pepakura, but that just shifts the blue lines around on the model viewer and the unfold, so it doesn't really help much.

My initial thought is maybe the decimation in Blender caused some weirdness, or maybe the models themselves need vertices merged somewhere. I'm new to using both Blender and Pepakura, so there's likely something I'm missing there too.

TL;DR: Pepakura unfold look gross, how fix?

 

[PlanetAlexander]

Blender's decimate modifier/function is good at reducing polygons, but not too neatly. Pepakura may not be liking how Blender is "remeshing" it essentially. A couple of things you could try is to merge all vertices by distance, or degenerate dissolve.

 

[LeastFamousStev]

Ah, so I was on the right track! I'll give those a shot and post my progress

 

[LeastFamousStev]

So far not much success with merging verts or degenerate dissolve, unfortunately. With the latter I can get some cleaner surfaces but also it's easy to produce a lot of N-gons. I'm gonna try working with Blender's retopology tools next.