Perfect circular hole on curved surface.


What is the best way to get this result?

Doing this on ploys and making it look great when you convert your model later to Sub-Ds.

Is there other ways expect making a cylinder and spanning or boolean or maybe even convert to nurbs and trim it or maybe some werid cutting and moving and hoping on the end it will work out awesome?


There is a thread about theoretical sub-d in the max forum which have discussed this problem, the thread is lengthy though =)

 If you're not using max, at least the basic process is there.
 This tutorial for Wings3d also describes the process in a different way.


I would make it this way (Lightwave):



You’d need nurbs or some other trimmable kind of surface to do this perfectyl. I guess this is why nurbs are still around.

If you’re not needing a perfect result (in tehnical sense), gerardo’s method seems great



I guess using nurbs trim or boolean is really the only pretty quick way of getting a nice circle.

I saw in one of those thrends that sigge put up had a kind of good idea. The idea of making a nurbs circle and using something in Max called ShapeMerge. I use XSI though and I haven’t been using it very long [2 weeks] and Im not even sure if they have such a tool there. I was a Maya user before that which I can’t even remember if Maya had such a tool. It seems to be like a nurbs projection thing but on ploygons. I think thats pretty crazy.

On another note I was reading about how they were making boxs in that thrend and they said that bevel [or chamfer] didn’t get the best results and its better to cut the cube how they did it.

I tried out something and I did notice that bevel was not doing it as good as the 3 Sided cut method. That way though took way longer then the bevel method and would be extremely difficult to do on a complex surface.

I started doing things and I found out that if I use bevel with XSI’s ROUNDING feature in the options I was able to get same or better results then the 3 Sided Cut Method and hell of a lot easier as well as faster.

I first thought that this Rounding thing would add way more edges then the Cut Method but for some strange reason it gives you the EXACT same ploy count and your box looks 100% the same way in Sub-D. It also looks MUCH cleaner and is 100 symmerical.

Ploy count 54.


heh thanks for the video. Funny thing is that I used this method before :open_mouth:


I encountered this problem when I had to make a bowling ball. How do you put on 3 holes at irregular shaped intervals?

Well, it wasn’t a technically perfect result, but the placement of the holes can make a big difference. If you use Sub-Ds, a square hole on a square poly will become a circle after a few subdivisions, so if you can position your hole so that it’s on a more regular surface, you’ll get some better results. And, of course, bevelling or duplicating the edges of the hole, so that you can see the circular rim better.


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