How to cut a circular piece out of a square mesh?

[Anonymous]

I found this file on NASA's website. It's a square .stl file that has the rough surface of the moon.

I essentially want to just cut out a circular piece of this square model. What is the best way to do this?

To this...

I imagine there are probably multiple ways to do this, any thoughts?

[laughingcreek]

This can be done with fusion, especially if it's a quad mesh (can't tell from pics).  However fusion is not particularly good at doing things with meshes, and it can be difficult to get a decent result.  This thread has some info related to what you are asking about.

https://forums.autodesk.com/t5/fusion-360-design-validate/how-to-work-with-irregular-and-organic-stl...

I would suggest doing this with a program that is made for working with meshes.  my personal favorite is mesh mixer, but there are others also.  This would be a fast and easy operation with MM.

[Anonymous]

Got it... thanks for the reply.

I feel like I'm a bit overwhelmed. My final intention with this is to 3D print.

can you briefly explain meshes and why Fusion 360 isn't well suit for meshes? If not meshes, what is it good for?

I don't do any real 3D design, but I run a 3D printer at work. Often people will ask me to do some basic stuff which I've gotten by with Fusion (previously I used 123D Design). Most of the time it is adding text to a 3D model which is easy enough in Fusion. I should really be using Mesh Mixer though if I want to modify an existing .stl?

In the mean time I'm going to download Mesh Mixer and try it out.

[TrippyLighting]

Fusion 360 is good for CAD geometry, which is a resolution free, mathematically precise description of geometry in form of BRep and NURBS. CAD geometry also has topology.

Triangulated meshes are a different and imprecise representation of geometry and have a fixed resolution. They also don't have topology in a mathematical sense.

These 2 geometries are somewhat incompatible. You simply loose data when exporting a CAD model into a triangulated mesh. As a result re-creating CAD surfaces from triangulated meshes requires a bit of work/skill/knowledge and I would think is not really necessary for what you want to do.

In your case Autodesk Meshmixer is probably a better tool for this.

[laughingcreek]

Fusion is good for solid modeling using brep/nurbs.  Brep models and mesh models are completely different types of models/data sets.  Think vector lines vs rastor images, but in 3d.  Fusion is great for outputting a .stl file, but not great at importing one and doing meaningful work on it.  The available mesh tools in fusion are lacking.

[etfrench]

Import the stl into Fusion 360 (or just determine the size circle needed.

Create a sketch with circle and rectangle(larger than stl)

Extrude the cutter:

Note: The extrusion should be higher than the stl.

Export the cutter as an stl.

Import the NASA stl file into MeshMixer.

Import the cutter stl file into MeshMixer.

Select the NASA stl in the Object Browser, then select the cutter stl.

Select Edit|Boolean Difference.

I wish I could tell you what settings are needed in the Boolean Difference dialog, but I've only been successful once out of five tries 😖

[MoshiurRashid]

Try Autodesk Meshmixer for this job. Import it in meshmixer and get the portion you want. Meshmixer is a free software from AUTODESK