Best way to intersect cyllnder with plane and re-topologize it?

Disclaimer: I am new to 3D modelling and have been following various video tutorials to learn. I am using Blender 2.83 to create assets for a game.

I am creating a model of a suitcase with a cylindrical handle. The cylinder of the handle must intersect with the planar face of a supporting structure which attaches the handle to the case (see image below).

For the modelling process I am trying to keep my entire geometry out of strips of quads. This is following advice I have seen repeated in tutorials. At a high level this makes sense - strips of quads are easily manipulated and seem to work well with the various modifiers and tools. Please feel free to correct me if this is a bad practice.

To achieve this intersection I tried two things:

  1. First using the boolean union modifier. This created quite a mess.
  2. What worked better was:

I intersected the cylinder with a single quadrilateral face, and then did the knife intersection. Then I cleaned up the topology as best I could by using loop cuts, the knife tool, and manually adding some faces. This is the result of my first attempt:

I did get the quads I wanted, and they form “nice” loops with the cylinder (as best I can tell this is a good practice). I have some questions:

  1. This whole process was a bit slow. Is there a better way to do these kinds of intersections and get a better topology automatically?
  2. Am I wasting my time by trying to create this cleaner topology?
  3. There are some visible creases that I think are resulting from my very squished quads + sub-surf modifier. Any thoughts on how I could improve this? (See link below)
  4. Less relevant, but I am still curious: Even though I have shade-smooth (and sub surf) turned on for the entire model, the cylinder still appears quite faceted. I’m not entirely sure why.

I could not upload the blend file to this site (new user), so I uploaded here if you would like to take a closer look:

As a new user, I also could only upload one image. To see what I mean by creases, take a look at:

The cylinder of the handle must intersect with the planar face of a supporting structure which attaches the handle to the case

I want to ask this: Does the cylinder has to be connected (welded) to the face or would it be sufficient that it looks like it is connected? So, would it be enough to just let the cylinder stick through the face a bit?

I am asking because I am no expert and want to know this. I think, for a game engine, it would be sufficient to try this simple solution. Although I would also be interested in the modeling part. :laughing:

Embarrassingly that possibility did not occur to me. For whatever reason I thought they had to be one contiguous mesh, but in hindsight it seems silly. I can’t think of a reason they can’t be two separate pieces. Practically speaking you probably solved the problem, although I am still interested in getting answers to my other questions (if purely for the purpose of learning).

Thanks again @BlenderSL

the basic way to get a cylinder merged with a cube is this one:

Create your cube, cut a hole, extrude inwards:

Make your selection a circle with Alt Shift S (To Sphere) or with the LoopTools addon > Circle:

Extrude up:

You don’t need the first extrusion. Simply select the virts, make circle, delete the face and extrude up.

mmh not sure to understand what you mean :wink:

If you extrude down, make circle, and then extrude the top loop up you will create a pole at each point around the top circle. By avoiding the extrusion down and deleting the faces, you don’t create any poles.

If the “cylinder” needs to travel inside the cube, after extruding upwards, extrude the top of the cylinder in to add depth, and then extrude that down.


This is a clean topology.

I may have not understood the initial question

Thanks @moonboots and @Roken, that is indeed a much faster way to do what I originally did. Will keep this in mind. :smile: