Hello, geometry which I want to modify is pretty flat and open (it’s a surface of stairs). Giving it a volume would be waste of polygons. But I want to add some form into it by subtracting geometry from a subtool. For boolean operations I have to have active Dynamesh, right? Problem is, that Dynamesh is closing my geometry damaging everything and doubling polygon amount.
Please provide some solution.
Try going to “Preferences > Geometry” and moving “DynaMesh Close Holes” slider to 0.
Thank you for your response, unfortunately this is an effect:
Didin’t help.
Giving it a volume would be waste of polygons.
X x Y x Z = VOLUME. You could have a box with 8 vertexes, big enough to hold a cruise ship or a canary with 300 M points. As soon as you start to think about using DynaMesh, you’re going to have lots of points. But you NEED the points to describe the geometry.
I mean as soon as I make it closed geometry by obviously adding depth I will gain extra unnecessary vertexes.
Anyway I got what I wanted, but unfortunately with geometry on the back too.
Not a problem is it? You could delete it or hide it.
there is no other way when you work with dynamesh. It should be a volume.
You can of course delete the extra geometry after you did you dynameshing or even do a localise remeshing and reproject on a copy of your original dynamesh objet.
Thank you for your advices. 
no problem we are here to help… even on sunday 
