Model rail locomotives for 3d printing

Hi. I am using sketchup 2017 for 3d printing. I have created a model of a locomotive shell, but am having a problem exporting it as an stl file which is necessary for the 3d printing. The shell is intended to fit onto an 0-6-0 chassis. The model has a number of components, eg the various handrails are components, however, when exported they do not appear on the stl version of the model. When I ‘explode’ the components the export process displays an error.

Should ‘export STL’ be able to handle components, or would it be better to ‘explode’ any components, but then why should this create errors when exporting?

There’s probably something wrong with the model. Share the SketchUp file so we can see what you are working with.

class03-1x-complete(3).skp (4.5 MB)

I have uploaded the SU model.

Your model has a lot of problems. If you make a group or component of the thing and run Solid Inspector2 you will see most of them listed.

It will be able to fix a few of them but the majority will require you to get in there and deal with the stuff.
One thing it doesn’t identify is the reversed faces. Those are shown in blue while the front faces are shown in white.

You cannot have any exposed back faces in the model. They identify which side of the face is to aiir and which side to the print media.

I note you also have a copy of the half body at a huge distance from the rest of the model. This can create problems for you. Delete it or at least move it close to the origin.
Screenshot - 6_14_2024 , 8_35_31 AM

I’m guessing you started from an imported .stl file. Is that correct? If so, I would suggest starting over in a new file but import the .stl with the import units set to Meters instead of Millimeters. Starting over correctly will likely result in less work than chasing down the thousands of problem spots. In Model Info Units, also change the units to Meters and turn off Length Snapping. Importing at the larger size will make the model easier to work with and make it possible to keep the smaller details and avoid the missing faces (identified by Solid Inspector2 as surface borders). There’ll be no need to scale the model down before exporting the .stl. Export it with Model Units set to Meters and import into the slicer with units set to Millimeters and all should be well.

Thanks Dave, Yes I used Solid Inspector, but didn’t know how to correct the faults. Yes I was importing the half model, but couldn’t find it. I will try again using your suggestions.

No I created the model from scratch with the units set to mm. I used drawings of the locomotive - side, top, front and back views.I scaled the drawings to match z gauge (1/220 scale).

I had previously used Blender, but that was about 10 years ago and I am afraid I have forgotten how to use it. I thought Sketchup would be simpler, but I am having my doubts now. Blender had a way of ensuring that all faces faced the same way. Sketchup doesn’t appear to be able to do this or does it?

There is no reason you can’t make a model of this locomotive body in SketchUp that is suitable for 3D printing. As I told you, though, do the modeling with the units set to Meters and create your model so 1mm in the printed object equals 1 meter in SketchUp.

If your workflow is correct you shouldn’t have issues with reversed faces but if they appear you can easily correct them by right clicking on them and choosing Reverse Faces.

All of these were modeled in SketchUp using the method I’m describing and there was no problems with getting solid objects. Even the screw threads are properly modeled and work fine.

3D Printed Connecting Rod

U-Joint 3D Printed

U-Joint 3D Printed
The tapered pins aren’t driven home so the thing can be disassembled.

Here’s another example.

The reulting .stl file opened in the slicer.

Check out this Thread. There are other examples in the forum.

I would recommend as another way to inspect and also make something a solid. The plugin hasn’t been updated in a while, but I found it be irreplaceable in making something 3D printable - especially from an imported file. Try the free version and see what it tells you about the model.

A fantastic model RLGL, and what looks like a useful extension John.pacyga. The free version shows lots of faults, but it looks as if I will have to purchase it in order to get rid of them…

Just as a matter of interest. I am trying to attach handle components to the body of the locomotive. The bottom handle is fine, but how do I cut away the body section for the upper handle. Both handles are hollow and were attched with the move tool so that the bottom of the component contacted the face.For the long handle the it broke through the face, but that was not the case for the short one. ???

That has nothing to do with using SketchUp Make and it won’t be fixed by switching to a paid version. It’s strictly down to modeling workflow.

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