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I am modelling a complex man-made shape from measurements of a real object. I am using the boolean CSG modifiers to generate most of the geometry. Most of the shapes in the object lend themselves to well CSG, but also having the modifier stack there means that if I make a mistake in measuring or whatever I can easily back up without having to repeat the whole process again.

Problem: as I create new geometry using union, difference and intersect, small pieces of degenerate and loose geometry appear. This happens even when the geometry is 'perfectly' aligned. Sometimes they can be avoided by over-sizing or under-sizing the second object or introducing a false overlap. However, that is often not practical.

What I need is a way of cleaning up the geometry in the stack in the same way as the tools in edit mode, but via a modifier. Remember, I need to keep the stack. Anybody know if any of the available modifiers do this please? The planar decimate modifier is very useful for removing extra edges but does not remove 'empties'.

Also, What is the best way to get two edges perfectly aligned so the end vertexes occupy identical coordinates? Snap seems very hit and miss and not 100% accurate.

Thanks in advance

Stephen

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  • $\begingroup$ Boolean operations do not like coplanar or tangentially touching surfaces at all, for the Boolean modifier to work well your objects should always have very clear intersection with generous gaps whenever possible. That should take care of most of the artifacts you are finding. Unfortunately non destructive modifier based cleanup solutions do not abound in Blender, I don't think there are many options available procedurally, without applying modifiers first, there the Decimate modifier you mentioned and nothing else that I know of. $\endgroup$ – Duarte Farrajota Ramos Aug 5 '16 at 2:59
  • $\begingroup$ I have found one way of improving on snap - which is using the 3d cursor (snapping to the destination vertex) and then scaling the other vertex to zero; this allows you to cull one or more axes. $\endgroup$ – Stephen Parry Sep 5 '16 at 1:50
  • $\begingroup$ Blenders implementation may not like coplanar or tangentially touching surfaces, but from experience of other packages, that is a flaw in blender. Some simple shapes (e.g. a simple L shape made of two equal sized cuboids) cannot be made without co-planar surfaces. At worst CSG routines should allow you to specify a tolerance within which two points or surfaces are merged. $\endgroup$ – Stephen Parry Oct 7 '16 at 15:05

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