Creating A Perfect Hole In A Cylinder?

Playdo

Hi, can anyone explain how to get a perfectly clean hole in the side of a cylinder using as low geometry as possible? It's to be subdivided and I'm having some issues with deformations.

What I've been doing so far is selecting 4 'square' polys, producing an 8 edged vertex in the centre and then chamfering and spherisizing the result. I then extrude the resulting poly inwards to produce the hole and add the control loops to tighten the edges. I'm working on a 16 side cylinder.

ps I'm using 3DS Max

renderhjs

a screenshot would help

Playdo

Yeah I had one ready to go but couldn't figure out how to upload it. Does the image need to be stored on an image site and then linked to it?

Playdo

Ark

What you are doing looks ok, just add another edge loop on the outer edge.

praxedes

I have a method but it may not be the best way- it's a kind of "fake" boolean I suppose- create another cylinder at 90 degrees so it intersects where you want to put the hole. Delete all the faces except one circular end cap, then use orthographic views to move its vertices forward and backwards to line up with the curve of your main cylinder, preserving the circular shape when viewed head on. Combine meshes, delete faces to accommodate the circle and target weld the verts together- then select the circle you just welded in and extrude it inward slightly, then delete these faces. You are left with a hole which is perfectly circular when subdivided.

Hope that makes sense- I've used this technique quite a lot on my recent model cos it gives a really clean result on curved surfaces without having to bollean and rebuild the mesh.

~P~

Playdo

Ok thanks. Ark- tried that but it produced more pinching, not sure why you'd want to add an extra loop there?

Praxedes- I understand what you mean. Saw a similar tutorial a while back but didn't get great results (though I think I was trying it with a low poly shape so I'll give it another go). Instead of deleting the faces and merging the circle they used the circle as a guide to align the existing vertices of the model (using edge or face constraint).

ps. I can't see my images posted above, only crosses, anyone know what setting I need to change?

Ark

Normally it helps with pinching. Try add more segments to your base geometry before adding in the hole.

Also about your images, you need to link directly to the image instead of the page containing the image.

Playdo

Cheers Ark. Ok, I thought it may have something to do with the resolution of the base geometry. So what's the usual procedure if more geometry is needed before cutting a hole?

Ie. do you do all the modeling at a low poly level and then subdivide down to the end level and then cut in any holes at the end? I still feel like a beginner at this and it's got me confused.

commander_keen

Its not possible to make it perfect. You just have to tweak verts until it looks right. You can make it "perfect" with nurbs, but generally nurbs models should be converted to polys to add control edges before rendering so you end up with the same problems.

Tumerboy

nurbs models should be burned with fire.

Playdo

C.Keen- Ok maybe not perfect but I'm looking to avoid any of the deformation that I've been having. There's always a technique to do things more accurately. ps I miss the ease of doing this in several clicks using nurbs.