3D modeling Circles and Manifolds oh my!

Producing manifold objects in sketchup when the shapes are round is horrid. Because the segments often don’t weld to other rounds, i’m always getting errors and having to use other tools to fix them.

Any tools out there to help?

Also, I have a particular object which appears to be manifold, but every program i attempt to fix it with, says otherwise. It either fills in my tube, or capps the ‘cup’. I don’t get it.


This comes from your work flow and the small size of the object. Your model has the the problems shown by Solid Inspector.

You can see where the internal faces would be in yours on the right and that mine has no internal geometry on the left.

You can change your work flow to deal with this easily enough. One way is to use The Dave Method.

With the right work flow it isn’t difficult to make rounded objects that are manifold. For example, the bracket with the hole in it is a solid as are the other components in this model.


You have planes that coincide and are distorted, and voids within voids. So it is more a matter of constructing the model so that these things don’t occur. The coinciding faces are seen by the slicing software as 2 faces without any space between and therefore no volume. Also, the slicer generally creates the wall thickness. So you don’t need to - as it appears you have. Your model (in this case) should be 1 simple container. To ensure alignment of circles, always construct them with the same number of edges, dragging to the same cardinal point. Move parts also along the same direction for set distances so they can be replaced accurately if you need to prototype some elements. I often construct the whole component as a shell with little internal geometry and then separate out parts in groups so they can be moved sideways easily. Each group can be worked on and then moved back. They will always line up. I attempted to repair your model, but it really needs to be rebuilt from scratch - which, following the advice above should be easily a success.

Great approach! I’ll definitely give that some practice.

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