How to I smoothly merge the seams of this cyilinder into the rest of the chassis on this tank?

How to I smoothly merge the seams of this round cyilinder section into the rest of the chassis on this tank? Like what’s seen in the real-life photos of it.

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Boolean the cylinder into the hull, clean up any stray geometry, select the edge loop around the base of the cylinder and use bevel to add the curvature needed to blend the two parts together. Adjust edge sharpness / smoothing groups as needed.

If this model is going to be used as is, without subdivision, then this approach should be fine. If you wanted a more nondestructive / procedural approach you could use the bevel modifier and either vertex groups or edge bevel weight. For a subdivision model you’d have to add more supporting edge loops.

I tried that, but I’m probably not doing it right, I’ve only been doing 3D for about a year now, and am not very experienced at it yet.

Could you please do this for me? And fix any other problems you see with it? Like ngons and uneven surfaces?

It’s a very simple mesh.

https://1drv.ms/u/s!Ansq7V5Mt2BrgRk23FD9WkW1TpS7

Here is what happens whenever I try to bevel the edges after using the boolean difference between the cylinder sections and the chassis.


You can also use shrink wrap.
Don’t have enough time to explain but see attached blend and image, let me know if there is something you don’t understand. There are probably faster ways, this takes about 30 seconds at the most.Shrinkwrap.blend (510.4 KB)

I took a brief look at the mesh you provided and it looks like you have a lot of non-manifold / loose geometry and duplicate verts. The bevel error you’re seeing on the front slope is also caused by the face normals pointing inward.

To fix these issues you’ll need to clean up double verts, non-manifold / loose geometry and recalculate the normals so they are all facing the outside of the model. Once the model is cleaned up the bevel tool will work as expected. Depending on the width of the bevel you add you will also need to do some manual cleanup where the top of the cylinder meets the top of the hull.

I’ve attached a blend file with the cleaned up hull inside of it so you can see what I did to the geometry. In the example blend the edge loops are already selected so you can hit ctrl-B and adjust the bevel tool accordingly.

T28_HullCleanup.blend (514.3 KB)

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Thanks for fixing my chassis, but how do I bevel the edges without distorting the surrounding mesh and creating terrible ngons?

The front cheek plates are flat surfaces (angled in several directions) with compound miters. A lot of the geometry problems you’re running into are caused by the face in that area not being coplanar (flat). If you remove the cylinder shape and triangulate that face you’ll see that you end up with a concave shape.

If you run a boolean operation on a face with noncoplanar geometry the resulting n-gon will triangulate in a way that won’t shade well. Since the bevel tool is trying to follow the edges of these triangles you end up with something that doesn’t look good.

In the example image below you can see how I removed the the cylinder from the face, triangulated the face and ran the boolean operation again. While it’s not perfect it is closer to where it needs to be. To prevent errors like this it’s best to block out the larger shapes with compound angles / cuts and try to keep the resulting faces coplanar when you’re running booleans.

I had to manually merge down some of the verticies in the spikes that the bevel tool left behind. I’ve uploaded a blend file with the one side done and the other side ready for you to try beveling.


The settings I used for the bevel tool were a bevel amount of .1 and 3 segments. You’ll need to merge down the verticies highlighted in the image.
T28_HullBevel.blend (494.8 KB)

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Thanks! Can you please do the same thing on the rest of the tank parts that I applied your fixed chassis to?

I made some changes

https://1drv.ms/u/s!Ansq7V5Mt2BrgRp0c-zPPCLzyPNe

Could it be smoothed using sculpting?