Cleaning booleans on same plane height (lots of degenerate, isolated verts/edges, hard to clean)

Raphael_Bouch

Hello polycounters !

Everyone knows how booleans work and how cleaning is always required. But overlapping booleans on the same surface plane seems to be infinitely harder to clean

So far the only method I found fast enough is to select the caps verts in side view, delete, and then refill the surface with an n-gon that I would rebuild topology on later. But is there a more reliable, faster and easier way to do this annoying cleanup work ?

I am using Blender and the fast or exact solver don't change anything.

Thanks in advance for any help !

gnoop

Booleans don't like coinciding surfaces. it's a fact.  But IMO works pretty nice in Blender anyway  with almost zero shading issues.   Try to use less tessellated geo.  Less edges is better .  Also in my experience booleans work nice  when your model is  few meters sized . Too small and it's not enough  precision in numbers.  They also work best for closed "watertight"  meshes.

I usually put decimate  modifier after . It cleans  redundant vertexes automatically while also keeps normals intact mostly .

Just keep in mind   booleans works fine for  vertex normal based shading and low poly geo for games .  It wouldn't work for sub-dive . You would have to create your own edge flow on top of it at least .   Same as  for meshes imported from CAD soft

ps. And sometimes you would still need to fix vertex normals manually  to kill shading gradients.   Don't get rid from initial primitives too soon. They could be helpful to transfer vertex normals  using data transfer modifier.   That said  recent Blender versions  keep vertex normal based shading  very  nicely through boolean and decimate modifiers.   just don't forget to check in "keep normals"  in final triangulate modifier   I also usually put after  decimate.

Look how last boolean cube is cut trough  cylinder   and leaves zero shading  gradients .   That's a power of  Blender

Michael Knubben

One nice thing to be aware of is that a Boolean modifier set to 'Collection', with no collection selected, attempts to merge all coplanar faces. Additionally, a Decimate modifier set to 'Planar' can use materials to limit the decimation, which really helps.

Meshmachine also has a few nice tools to fix the results of booleans, like double verts

Ruz

there are some good resources on booleans
https://www.youtube.com/@JoshGambrell
i quite like Josh's tutorials, very informative, though he does used some addons