General support material

[roblangston]

Hi,

I have been using Simplify3D for a while and have just come across a problem with one of my models when trying to automatically generate support material.

When imported, the model looks odd in the preview window (almost as if parts of it are hollow) see below:-



However, the model is manifold and passes all checks. When I enable cross section mode and cycle through the model it shows correctly as solid



I have tried altering the overhang support angle without success. The automatic support generation does work for other models I have but not this one for some reason.

It does let me manually place support material but as this is a simple shape I thought the automatic placement should work.

Sorry if I have missed something silly. Otherwise, any ideas?

[roblangston]

Managed to solve the issue by importing into slic3r which carried out 468 automatic repairs. Re-exported to STL and then imported to Simplify3D. After this automatic support generation works as expected. It must be an issue with the stl export from Sketchup or something funny about this particular model.

[Memnarch1113]

When exporting a file from Sketchup, it's important to make sure it's manifold (i.e. it's a solid). I typically use the Solid Inspector extension to make sure that there are no extra lines, holes or interior faces, which can confuse slicers. This is also helpful for using the solid tools in the pro version of Sketchup. Alternatively, Microsoft has a fantastic online service called Netfabb which can repair your model for free (you only have to sign in). When you see an object that looks like yours did in Simplify, (where the walls aren't solid), that means there is a problem. Usually, Simplify will have trouble generating supports for it.

[dsegel]

Load the original into S3D, select Repair->Flip Surface Orientation and then click on the side that looks wrong. Does that fix it?

[roblangston]

Hi,

Many thanks for the replies. Solid inspector shows no problems within Sketchup, the model is manifold. However, doing as dsegel suggested flipping the surface orientation fixes the issue. I would be interested to know what this does exactly?

[Joao]

You might already know this but on SketchUp each face has also the concept of 'sides', rear or front.
If your solid has a face with a reversed face, S3D will get confused with that face and most likely present it transparent, and slicer can even ignore it.

On SketchUp the back faces are darker than the front faces.

If you get a back face that was supposed to be the front, just swap its orientation.
Look here:

The middle cube has a face that is not correctly oriented. Select the face and choose to invert it.
And thats it.

I found that most of my slicing problems with S3D were related to this, Cura and Slic3r for some reason ignore or fix it for the slicing.

[Memnarch1113]

Faces of objects (at least in Sketchup) have a have a property that defines one side of the face to be exterior (white) and one side to be interior (blueish/greyish). If you have a face backwards, with the interior facing out, the slicing program will be confused. This is easily fixable in Simplify with the reverse faces repair, or in Sketchup by right clicking on the face and clicking "Flip Face" (I believe it is called). I was under the impression that it would show in Solid Inspector, but I guess not always.

[roblangston]

Many thanks for all of the excellent replies. I had completely forgotten about the front / rear face options. I just assumed as the object was solid everything should be OK. I did think it must be a model problem rather than a bug as all the other exported stl files i have produced had their support material generated correctly. Thanks once again.