Elementary Question about loop cuts and a half around

So I am feeling pretty ignorant at this point. I cut this in half with a boolean tool but now I can not make a loop cut go all the way around this half round pole. For some reason its stops. Its going to be a bit tough to make the subdivision surface modifier work right if I do not get this figured out. I did make a face on the flat edge. It is a quad so I do not know what else to try. I also found out I do not understand the bisect tool. It must only cut faces. I have been studying topology and quads and poles and such but here I am stumped. aQuestionhalfRound.blend (542.5 KB)

There’s definitely no face in the blend file you attached. Fill that area with a face and it works perfectly.

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So I am selecting all the edges on the flat part and I do make a face but it wont go all the way aournd

2QuestionhalfRound.blend (552.9 KB)
I am doing something wrong when I make the face ?

I am using top view and I am selecting the edges with xray select all boxes and then I press F and it dose seam to make a face. But I must be doing something wrong

Here’s a quick video showing a quick way to fix it.


For some reason I have a empty place where there is not a face I box select all the edges on the down view and then I press F but its leaving a empty face for some reason.

Wow ok. Thank you !

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See my video above. If you switch out of wireframe mode and look at it in solid mode you’ll see some of the issues. The flat face at the back isn’t connected to the correct vertices. There’s also a couple of missing faces and a stray edge.

Basically: Switch to wireframe mode, delete all the verts in the whole middle, delete the stray edge. Extrude the top back down to the bottom, snapping to the bottom piece, A to select all then Alt+M and remove by distance to clean up the doubles. Then edge loops.


While there are solutions above, sometimes “order of operations” will make your life a lot easier.

In a RW machine shop, sometimes you MUST do operations in a specific order. The same applies in the (infiintely more malleable) virtual world: in this case slicing up the cylinder before booleaning may be much easier. Something to keep in mind.

Also, other apps sometimes have tools that make such operations trivial: in C4D for instanance, the Knife tool would make short work of this. OFTEN I find equivalents available as addons for Blender.

Although I find addon proliferation problematical (it’s just so hard to remember them all!), it’s a good problem to have.

EDIT: all the things JM1970 say above are Good Practice.


Making a half-cylinder:

  • add a cylinder
  • in edge mode select all vertical edges on one side (do not include middle ones), for example in front view with x-ray box-select them
  • dissolve edges

Result is a water-tight half of a cylinder. No Booleans required.

Stan That method of dissolve edges is not working for me. Also I am a bit confused about the top face going away as well. Maybe i need to start with a cylinder with a grid fill

Also what is to become of the faces on the top of this half round top ? I have 2 options grid fill and triangle fan.

I still have a lot to learn about topology. question.blend (579.7 KB)
I am not able to see the mesh that is taking place on the very top of the pole. Even when I turn on the visibility I can not see the fan or the ngons on the top. I was able to create a half round pole by flattening one side of the round mesh mesh. At that point I could still use the subdivision modifier.

Make sure you are in edge mode when you’re selecting, and only select the vertical edges. Don’t include any horizontal ones. This is how such selection should look in x-ray view: