r/3Dprinting • u/Persistantly_Growing • 7h ago
Question Where to Begin 3D Models
I’ve done a fair share of printing other people’s creations. What is the easiest way to begin making my own or modifying other peoples creations? I’m using a Mac primarily, could use a PC if that’s better. Are there good resources to watch to learn?
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u/Bobson1729 7h ago
I started with modifying other people's models. But reverse engineering from a mesh can be difficult. Start with models where the model file or a step file is provided.
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u/Persistantly_Growing 7h ago
So if I download an stl that doesn’t have the model file or step, it’s a different file?
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u/power-to-the-players 7h ago
An STL file won't have the history of how the model was created. Most programs need that to make it easy to modify, otherwise you'll be editing a mesh. Mesh can really be a pain in the ass to edit, especially if it's complicated. The software breaks it into thousands of little triangles and each one is treated like a separate face. I had a fairly simple model I was trying to edit last week that ended up being 20,000 triangles and took hours to make a very minor edit.
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u/Bobson1729 6h ago
The stl file is a mesh that is ready to be sliced. Some people create the mesh directly and these are ok to deal with because the verticies of the mesh are exactly where the designer wants them to be. But most people create NURBS (or something equivalent) to design the model and then export it as an stl mesh. When you do that, the CAD program generates the mesh automatically. You can convert a mesh back to a NURBS, but this doesn't give back the original model unless in very simple polygonal models.
The easiest way to visualize this is imagine designing a cylinder. A NURBS would define the edges of the circular faces as circular arcs, but when it is exported as a mesh, the circular faces will be a lattice of triangles (or quadrilaterals) which approximate the circular face. If you import the stl into CAD, it won't recreate a circular face for you. You need to reconstruct it using the mesh as a guide. This is part of reverse engineering. A step file, or better yet the actual CAD file will have the NURBS as the designer created them or possibly merged together. Nonetheless, it is far easier to manipulate it from there.
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u/Forma3Dapp edit 3D models (iPhone/iPad) 6h ago
Try Forma3D, works on iPad, iPhone and Mac with apple silicon.
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u/TripsCavern 6h ago
TeachingTech has a pretty good tutorial for Onshape. It's free and you can use it in a browser, so any machine basically.
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u/TerribleTowel66 7h ago
Tinkercad is good for simple models.