Why are files larger after transmutr?

No idea why, not done anything to warrant a larger file size than choose to start the proces to reduce the file.

I know stuff is just like that sometiumes.

What is the format of the original file? Is it a SketchUp file, or something else (fbx, obj, etc)?

1 Like

I’ve just discovered I’m having similar issues with converted FBX files being much larger than the original. I’m working with tree models and I think the size is is because surfaces, especially the leaves, are output as loose geometry within a single group. A 45MB fbx file converts to 135MB skp output file at 70% simplification. Without simplifying, the output is a 565MB skp file. It would probably be burdensome to implement, but if a single leaf object were made into a component, then replaced each object with an instance, that would probably reduce the file size dramatically. No small feat, I’m sure. The extra tricky part would be transferring the scale (size) and face normals (positioning) of the each object to an new instance of the component.

To test the theory, I used CLF’s Loose to Groups plugin on a subset of leaf objects, which worked great. I then made one of the resulting groups a component and reset it’s axis to match the UV origin (lower right corner). Then I used Thomthom’s Component Replacer plugin to replace all the other groups with the new component. It also worked great and the instances were in the right place but positioned to default normals, so they were all facing the same direction. Unfortunately, when I then tried the same routine with the entire set of leaf objects, it was taking forever just to handle the first step, with Loose to Groups,. After 5-10 minutes, SketchUp was still grinding away at the task, so I gave up on it. I don’t know how Transmutr handles conversion, but if it could manage this process without tanking like Sketchup did, that could offer a vast improvement in reducing the converted output file size.

Geometry simplification would probably still be necessary, since the original fbx file contained about 1.2 million triangles, but then again, maybe using components would offset that as well. Idk.

Just my two cents. :v:

If the model/file was .skp there would be no need to convert it, I should have stated converted .fbx.
I know sketchup can bloat file sizes due to lagacy bugs but these things grow massively.

I’m not surprised by these numbers. The SKP file format is very inefficient. It’s better since SketchUp 2021 (it’s now compressed), but Transmutr v1 still generates SketchUp 8 files for backwards compatibility.
Transmutr v2 will allow you to choose the SketchUp version of the generated files.

SU2021+ files are about 2x smaller than files from SU2020 and below. But they will still be larger than FBX files.
The FBX format is just inherently more optimized than SKP format. There is not much Transmutr can do about this.

Your idea about replacing loose geometry with instances is interesting, but this would require a lot of work (that will delay other stuff) and I’m not sure it would be that useful to many people. In cases like yours, with hundreds of thousands or millions of faces, you should use proxies. Or if you need them inside SketchUp, you should massively simplify them.
There is also a big tradeoff: your technic reduces the file size, but also reduces the performance of the file. It’s harder for SketchUp to draw millions of instances, than to draw millions of loose faces. So if you have several of those million-faces trees, navigating in the file becomes really slow.

Yes, I assumed it would not be practical even if you had time to work it in because it could dramatically slow down file conversion. The tradeoff is a bit surprising, but after thinking about it, I guess it makes sense. The extra step(s) needed to fetch and manipulate a component would take more time than simply drawing from the loose geometry. I hadn’t considered that, so thanks for pointing it out. :v:

1 Like

Along the same lines,as @Mike1158 noted above, I wouldn’t need to convert it if I didn’t need (want) it inside Sketchup.

Ideally, I want to use easy, in-app rendering and avoid complex rendering apps. I’m using ArielVision (a lighter version of iRender nXt) for simplicity and low cost because I don’t need (or want) all the bells and whistles. Unfortunately, proxies are handled by layer/tag visibility, so the full component is still embedded inside the file. AreilVision and iRender work well for models created in Sketchup but are limited by the inefficiency of the SKP file format. Therefore, I’ve had to bite the bullet, export my Sketchup model (terrain and buildings) to Blender, and add the plants there.

  • UPDATE: I added 32GB of RAM (48GB total) to my PC, and SketchUp was able to handle my bloated SKP file (560MB). Saving changes took a mildly annoying amount of time (1-2 minutes), but working within the file and rendering it inside Sketchup (while I slept) was at least possible. Just be sure to extend the time interval for autosaves so it’s not holding you up every 5 minutes.

Obviously, this is not a Transmutr issue, but I felt it worth mentioning in case others stumble into this thread looking for answers to similar problems.

1 Like