Simplifying A Complex Model

ratsrolocosx · May 4, 2022, 10:40pm

Hello everyone. I am new to blender but I have spent many hours trying to figure out the best way to simplify a model so that I can import it into Tabletop Simulator. The model is a spaceship that I exported from Everspace using UModel.

It has multiple interior spaces - 1 that’s in the middle like a fighter bay; 1 in the rear in front of the rear engine that inaccessible from the outside; 1 that’s behind the nose that is also inaccessible.

My goal is to reduce the vertex count to <25k (opens at ~140k). I also think I need to remove any non-manifold geometry.

I was able to reduce the vertex count by using merge > by distance after selecting non-manifold edges/vertices. This brought it down to ~70k veritces. This combined with manually removing a ton of greebling with Ctrl + L and then using limited dissolve over the whole model gave me a model that was low enough on vertices for me to import into Tabletop Simulator.

And then I ran into the non-manifold geometry issue.

This is what it looked like imported into Tabletop Simulator. The model still looks sharp and detailed which is good, but it’s full of holes. It looked fine in blender, I think because it will still display non-manifold geometry but Tabletop won’t.

I’ve tried using the solidify modifier but I haven’t gotten it to work out. It increases the vertex count beyond 25k and I haven’t found a good way to reduce it further. After using the decimate modifier the model went back down to 25k vertices but the model didn’t import to Tabletop Simulator.

My current thought is that if I can remove the interior spaces of the model and fill them in, I would be able to get rid of a ton of vertices/non-manifold geometry.

I also want to remove any interior spaces because it would be impossible to see any detail like that inside tabletop simulator. Natively the model is ~400 meters long, and I intend to scale it down to <10 centimeters.

My problem is I don’t know how to quickly or easily remove the interior spaces or the non-manifold geometry. I can select the non-manifold things and invert the selection to hide everything I want to keep, but I don’t really know what to do from there to correct the non-manifold stuff.

Any help would be greatly appreciated. I realize this post is quite long so I hope it isn’t obnoxious to read/respond to. I would include more images but I can only put in one it seems.

joseph · May 4, 2022, 10:42pm

Have you tried the Remesh modifier? It will give you non-overlapping geometry, probably less of it, and if it’s still too much, you can use a decimate modifier afterwards

https://docs.blender.org/manual/en/latest/modeling/modifiers/generate/remesh.html

ratsrolocosx · May 5, 2022, 12:04am

I have been fiddling with remesh for a while as per your suggestion. I like what the modifier does, but whenever I try to minimize losses in detail, the model balloons in vertex count (up to hundreds of thousands from <25k). It goes so far that in order to get the model back down to 25k or less with decimate, there is a large loss of detail unfortunately. I have gotten a remeshed/decimated model to import into Tabletop Simulator, but even sized down to the size I would use it in game, the blurriness of the model is too eyecatching in my opinion.

I think one of the reasons it balloons so high in vertices is also because it’s remeshing the insides of the model. That’s where some of the tiniest, minute details can be found. I noticed that once I remeshed and checked the inside there were large blobs of geometry (vertices/faces and whatnot).

I also tried to triangulate the model (without remesh/decimate) because apparently that can be an issue when importing models into tabletop simulator, but I couldn’t actually import it after the triangulation for some reason. Not sure what’s up with that, but if I could get my triangulated model to import properly and display all the faces then I would be golden because it only has ~12k vertices.

joseph · May 5, 2022, 12:36am

Hmm ok… new idea, make an icosphere with 4 or 5 subdivisions and shrink wrap it to the model. This will preserve outside detail and get rid of all inside detail. You can then remesh the shrink wrapped sphere, for good topology

ratsrolocosx · May 5, 2022, 12:54am

I like your idea, so far what I have is this:

Is there a way to shrinkwrap the sphere so it fits right over the model, or is that asking too much of the shrinkwrap modifier? Before I did this I also made faces to seal off the inside of the ship model completely.

Thank you for your help.

joseph · May 5, 2022, 1:03am

You’ll need more geometry on the sphere- the more geometry, the more detailed the shrink wrap can be. I’d subdivide it a couple more times, but be warned, that’s a slow and intense operation. save before each increase, and push it as high as you can get until either you get the detail you want or your computer crashes

Okidoki · May 5, 2022, 6:13am

The hard truth is that this is essentially:

while exist(interior faces):
    select and delete
while exist(nonmanifold edge):
    select and close # making no n-gons
while exist(almost coplanar face):
    merge

There is no such thing as “quick”.

Luckily this seems to be symetrical… Maybe there is a more low poly version available in th efirst place?

ratsrolocosx · May 6, 2022, 1:10am

I wasn’t able to find models from Everspace online. After some failed attempts at other methods, I decided it would be best to manually go through the model and remove/fix/simplify as much stuff as I could after automating what was possible.

My process looked something like:

Manually Remove most of the greebling and tiny surface details w/ Ctrl + L
Select and merge non-manifold geometry by distance (took about half the vertices out)
Decimate modifier
Manual labor to finish model
Triangulate Modifier

It was actually quite relaxing, surprisingly enough. I found myself enjoying the process of zooming around the model merging the myriad of vertices that were millimeters apart, deleting faces and edges that would never be seen, and then creating my own geometry to fill in the gaps that were created.

By the end of it this is what I ended up with:

As you can see there is a gap on the top of the model near the back. There are also a lot of faces that look kinda warbly. Probably because the way the faces join together at those parts is wonky. I could probably fix those with some more experience. It seems that the non-manifold geometry wasn’t the problem, I think Tabletop Simulator just doesn’t like non-triangular faces. Overall I’m actually happy with the results, and will probably improve on the model at some point. Thanks for your help and suggestions.

Okidoki · May 6, 2022, 5:03am

ahh yes the only triangle problem with some kind of other 3d apps…
You may have a look with textures apllied… it may just be okay… and for the normal… depend on the face smoothing… maybe just select some areas and split them (for example blue to get ride of red stretching)

But i don’t know this ship so i can missread the information i see (better readable with this simple shading
and compared to with textures).

ratsrolocosx · May 6, 2022, 5:01pm

I tried my hand at simplifying another ship model from the same game, and it went much better.

I found out that a lot of the model had “doubled up” vertices. These were spots where there would be two vertices directly on top of each other with different edge/face connections. I was able to get rid of a significant # of vertices by merging by distance on the whole object with the sharp edges setting on.

I also got rid of a lot of faces by using decimate on the coplanar setting to 8 degrees. This didn’t take very much detail away, but it did get rid of ~20-30k faces which was great.

Aside from that I got rid of really tiny greebling with Ctrl + L as before, and simplified the cylinders on the top of the ship. Originally they had a bunch of tiny beveled edges which were unnecessary. I just went and flatted them by removing the edge & everything above it leaving an uncapped cylinder, and then I just selected the edge loop vertices and alt + p + f.

Of course it also helped to work on one side and then just symmetrize after.

There is still some tiny holes and stretched faces but I’m not really concerned with them for now to be honest, I think the model looks pretty good in Tabletop.