SketchUp - Repair STL

Published by Mattias Brennecke on

For 3D printers it is necessary that the 3D models to be printed consist of closed volumes.

However, *.stl files are structured in such a way that the surface is represented by triangulation, i.e. the approximation to the exact shape by triangles of different sizes. Why that's important you'll find out later.

Using the NinjaRippers I extracted a model of a Space Marine from the game Dawn of War Soulstorm. The *.rip files are not directly useful, so they were converted to *.stl files with Noesis.

Most slicers can handle *.stl files, but depending on the game, some of them are incorrect, incomplete, or not scaled. For this reason, I repair the files one by one using SketchUp.

To allow the program *.stl files to import and export, I installed an extension. For more information, see here.

When importing you can change the scaling as well as the geometry in the options. Under this point there is the selection called "Merge coplanar faces". As already mentioned *.stl files consist of many small triangles, but if this option is activated, triangles that lie on one level and have two equal starting points are combined, so that way squares, Pentagons, etc. are also possible. This makes further processing much more pleasant.

One problem is that some surfaces are not closed and therefore no complete volume is enclosed. These gaps must be closed manually. Another problem is the orientation of the surfaces. There are inside and outside face, so to speak. Of course, the outer faces must face outwards for the slicer to interpret the 3D model correctly. SketchUp displays outsides in white and insides in a bluish grey. If they point outwards, you can mark them all and right-click "Reverse Faces" to reverse them.

Of course, it is also possible that digital objects are only 2-dimensional. These must be converted into 3-dimensional objects so that they can also be printed. For a single surface the built-in tool "Push/Pull" is sufficient, for contiguous and non-planar surfaces I use the extension "Fredo6 JointPushPull". How to install this extension, you can read here.

Helpful for the repair is the extension Solid Inspector², for which I wrote an extra blog post. When all objects are repaired, everything should be visible in white. I created another 25mm round base and exported the single parts (body, head, weapon, equipment) as *.stl again. Later I will put them together in Oculus Medium. Correct positioning in SketchUp is possible, but can be a bit cumbersome. Translated with

SketchUp Alle Meshes
Categories: Programs


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