Cutting into a sphere

I have a sphere as part of a larger model. I want to keep its shape as much as possible, but need to cut other shapes into it, are there any tips or techniques for doing this and retaining the smoothness with no pinching or distortion.

Thank you.

Having enough geometry can help, and adding an edge split modifier can help too, example in which i cut in a sphere with booleans, with a subsurf modifier on top to add some more geometry, and in the end an edge split modifier with modified angle value to fit my need :

Thank you Sanctuary.

I’m trying to do something like this.

Im looking at the front indicator and on the rear wheel thewre is an air vent. I want to keep the overall smoothness.

Should I start with a very low poly sphere like 12 segments, or go high? I was hoping to use subD, but dont want curved edges where ive made holes.

Do you have a bigger picture of the object you’re wanting to model, the tiny one is hard to see.

A quick method is to apply the same boolean trick, example :

on the sphere the following modifiers :

result :

That way you can use your booleans for easy meshing and avoid the nasty lighting of the boolean mess thanks to the edge split modifier

I’ll give that a go. I just always like have clean topology.

Thanks Sanctuary.

If you don’t want to deal with booleans and keep a clean topology, here’s a simple modelling method, i detail a lot but in practice it’s fast to do :

Add an UV Sphere , press F6 and set Segments 34 and Rings 20

Top view, Press K and put the knife on that vertex

Click then press Z (to cut through the whole mesh) and C (to constraint the knife on angle) then cut like that

From then we could extrude, intersect etc… to build the indent but as i have already made mini-tutorials dealing with extrusion and intersections, i’ll use the cursor method instead :

Change the Pivot Point to 3D Cursor

Select that vertex and press SHIFT+S -> Cursor to Selected

Select those vertices and press S then Z then 0 to move them at the same height as the 3D Cursor

Select that vertex and SHIFT+S -> Cursor to Selected

Select that vertex and press S then SHIFT+Z (to exclude the Z axis) then 0 (so we move that vertex exactly under the 3D Cursor but without changing its height

Repeat the same for the other vertices


On those 2 faces, using the knife ( K ) cut that way :

This way you can do the cursor alignement to that vertex too

Time to get rid of an useless pile of edges , select those vertices
Press X -> Dissolve Edges (then press F6 and make sure “Dissolve Verts” is enabled)

Finally merge vertex 1 to vertex 2 ( W -> Merge -> at last or at first depending on the order in which you selected both)

You can then extrude inside the hole (maybe remember to change the pivot point to Median Point too )

In case you weren’t using a mirror modifier, to avoid doing the same on the other side, just press W -> Symmetrise then press F6 and change the direction to -Y to +Y

After that if you need to subsurf, you’ll have to add support edges, or crease them too