My first Project: Making a Slingshot for my 3d Printer

Hi Guys,

This is my first project and my first post.

I am trying to build an stl of a slingshot that I can send to my 3d printer.

I was able to bring my design in from another program, unfortunately it came in with some really complicated geometry. I am going through the process now of trying to round the grips of the slingshot by subdividing vertices and manually moving them around. The process is INCREDIBLY painful. Any tips for a first time blenderer (aka blunderer) on how to round out these grips? I tried using the sculpt tool but because so many faces run the length of the grip (see image) it just ended up giving really weird results…

Should make the Y-section separate from the grip and then join them. The way it is now, it looks like your grip is orientated 90° sideways from where you’d want it. Geometry is also a bit messy with how the tris are haphazard.

The grip is actually pointed the right direction, it is a ‘sideways’ style like what is seen here:

My issue is exactly what you are talking about. This was designed initially as a flat vector then brought out to openscad then brought out as stl to blender. The whole thing has really weird geometry that is making it hard to round the grip portion out, right now it is as if it were a perfectly flat outline of the shape I want that was extruded out. Thoughts on how to push a curved edge around the handle on this thing? Should I start over and try to build from scratch with clean geometry with this as a guide?

Ahh - I found another way to bring a file in from inkscape - didn’t realize this was a native feature of blender. This should simplify the geometry, going to play with this and let you guys know what I come up with:

Aha! I imported my svg, then was able to extrude and bevel. AFTER beveling I was able to triangulate to create a mesh. The triangulate feature in blender is much cleaner (creates parallel faces as opposed to the craziness of the openscad route above), then export as stl and clean it up in the free version of autodesk and netfabb. It’s manifold now and has some bevel - the original question remains, is there a good workflow or tool in blender to smooth this grip out? Beveled edge is better, but it would be great to really mold it!

Sorry about that. When I had a slingshot it was the “wrist rocket” style, I didn’t know of the side-grip variety.

SVG import does make a nice curve object.

You may still have to convert to mesh to export a file suitable for 3D printing. After converting to mesh, you can select similar>co-planar where all the tris are in the middle of the grip, redistribute faces with beauty fill, then convert with tris to quads.

I made something quick and dirty to approximate a similar shape and got this after doing those steps.

It’s also possible to use the decimate or remesh modifiers, but YMMV. The top or bottom surfaces may even be redone with quad fill (which can look even nicer), but for shapes like this it can be really finicky to make work.

Oh… If you really want to shape it to get organic contours… An applied remesh modifier (to get needed geometry - not too much though as it will lag) followed by editing the mesh in sculpt mode can make that kind of work easier.

Thanks pauljs!

I did exactly what you said: I re-did the fill for the top plane then converted to quads by remeshing. From there, I did some work in the sculpt mode and when I got it as close as I could I applied an aggressive smooth modifier which hid the sins I put into the object when sculpting.

I only sculpted the top half, I ended up cutting the bottom half off, duplicating the top half and scaling it -1 along the z axis to create a mirror image that I reattached below. I’m sure something like this could be done with mirror but I’m afraid I don’t really understand that feature of blender quite yet.

This is going to the 3d printer once the weather warms up a little bit.

Like the concept. Perhaps the method of modeling the handle is a bit choppy, however not wrong, per say. personally to avoid all those choppy edges i would have started with a plane instead of a curve and modeled it MUCH lower poly, then started using loop cuts to push and pull for the fingers with a mirror modifier for perfect symmetry… then subsurface (A LOT). By modeling it you avoid the bending tris that cut into the edges. it would look more rounded and smooth.

Besides my little pet peeve, Good job.