Dealing With Scaling for 3D Printed Parts

What are people doing for scaling 3D printed parts? It seems that most are smallish and if you’re going to have any significant details you’ll end up butting your head against weird geometry problems in Sketchup. I’ve tried:

  • Just fighing it, doing everything in mm and occasionally just running into problems and fixing them. If you end up doing a lot of edge rounding and other curved surfaces this becomes a disaster quickly
  • Dave Method ( The Dave Method ). This works OK for a lot of things but I’ve run into 2 issues with this, 1- I seem to always start with something that an idea that someone already has and it almost always needs some adjustment/scaling. Scaling the large part doesn’t translate to the small copy and you end up with things the wrong size, 2- I like to put all the parts for an assembly in the same Sketchup file, 3 or so parts, plus 2 versions (a big and little) get to be messy really quickly, or maybe I’m just not that organized, either way I haven’t figured out hwo to make this work for me.
  • Just scaling everything up by 10 or 100x and scaling it back down when I get ready to export. I usually did 100x, and I didn’t seem to have problems keeping track of stuff most of the time. There would be times that I would type 8 instead of 800, but it was pretty easy to see it didn’t do what you expected. The big problem would be scaling it down before exporting to .stl and not forget to go back. 1- I never know what scale my saved files are when I open them till I measure and i’m worried that saving them small and then scaling them up, a few times is introducing errors.
  • Basically the same as the last one but setting your units to m and pretending they are mm. This works REALLY well while modeling/drawing, but gets confusing when scaling/exporting. You have the same headaches as 1 and 2 above (scaling 10 and 100x), but there is also the headache of the decimal point being in the wrong place after you scale when you’re used to seeing it right.

What are you doing/what works for you?

What I would really like is the last one (using m as mm) if I could just export m as mm without having to scale it. I was hoping that the units choices in the export dialog would do this, it would determine what units are exported, like if your model is 10 something long then if you choose mm in the dialog it would export it as 10mm, but I honestly can’t tell what the units choice does.

Please explain this. There’s no reason that you should have any “translation problem” with this method. If you do, you’d have the exact same problem with simply scaling up and scaling back down or starting out at a larger scale (meters) and scaling down (millimeters) afterward.

There’s no reason you can’t do that. I frequently create small detailed parts in the main SketchUp model. The pulls and hinges on these cabinets were created in the cabinet model using the “Dave Method”.

The balls on the hinges are about 3/16 in. dia. and the escutcheon plates on the pulls are 7/8 in. across.

If I am looking to print a small 3D part, I generally rough in the dimensions that need to be exact, then use the Dave Method to add small details (things like small curves), but only if I need them that small.

1 Like

Sorry I’ve been MIA, other things to worry about.

It’s when I scale something in the piece that I’m editing that things get weird. like if I select the part of the larger object and use the scale tool to change the size of that relative to the rest of the object.

I guess I could probably get around it by using components and groups but I haven’t quite figured out what to do with those yet, it seems like when I start looking people all use them differently and all too often when it comes down to it I end up exploding them because they end up annoying me somehow.

The problem I’m running into is if I have a few parts in the same model is some things seem to cause sketchup to crash. I’ve figured a few of them out (like often using Fredo6’s stuff causes crashes, especially his roundover tool). I doubt it’s how “complicated” the model is, your examples if they’re fully modeled are much more complicated then 3-4 3D printer parts in a model, it just seems to make the crashing more prevalent.

I’ve actually come up with something that is dead simple and works really well for me- I just model in m representing mm (x1000 scaled if I’m importing existing STLs), then when I export the STL I do it in “model units.” when you open the STL in your slicer software it just assumes the units are mm and everything is perfect.

Simple, it works and no extra steps unless I’m importing existing models into my model.

This topic was automatically closed 91 days after the last reply. New replies are no longer allowed.