I’m currently modelling parts for an action figure where I don’t want do modify inside parts of the model. When I use backface masking both with brushes and for the mask itself it usually works. However sometime the masking pen and smooth brush bleeds into to the inside geometry. This is incredible frustrating as it’s hard to know if the backface masking is protecting the inside or just 95% of it. How can I be 100% sure not to modify the inside of this model. I don’t trust backface masking anymore as it seems to rely on the brush size and models size as well. I can’t use a technique that works sometimes and sometimes not.
To use backface masking with a Masking brush you need to hold Ctrl and then turn on BackfaceMask in the Brush>Auto Masking sub-palette. Backface masking is set for each individual brush.
That is what I’m doing. But it still bleeds through sometimes. Maybe 5 %.
How can I be 100% sure not to modify the inside of this model.
Polygroup the interior polygons (poly group by normals will probably work here–if not you’ll have to hide the unwanted polygons manually for the purpose of grouping), and then either mask or hide that polygroup while working.
It may be that parts of your model become “forward facing” as you rotate. Backface masking is an automatic and dynamic effect based on the normals of the mesh, so the shape of your model and its rotation relative to how you are working affect the masking.
Yes, it might be several reasons for it not working 100 %. I made the inner part its own polygroup. Then I hid the rest and masked it with the mask rectangle and now it seems to be completely masked. It just a bit of a hassle to do on more complex parts.
It just a bit of a hassle to do on more complex parts.
Complex models can sometimes take a bit of work to establish polygrouping, but once you do you canhide or mask those groups with a single click. Commit those shortcuts to muscle memory as soon as possible for maximum efficiency using ZB.
Polygrouping is king with zbrush masking, and masking is king when creating almost anything here. So I get it may seem like a hassle to work this way with more complex projects for sure but it’s just a part of the workflow here and you get used to it. The key phrase there being “seem like a hassle”, they’ve really added everything you need to fluently polygroup and mask here, it’s the heart of operations!
It’s actually a very solid way to approach modeling and polygrouping all the things on your model has many side benefits such as then being able to remesh with better accuracy, split subtools apart for better organization, panel looping, texturing and creating uv maps etc and the list goes on.
As far as taking part of the hassle away goes (eventually it’s not a hassle at all and you’ll have mastery over all the ways to do this quickly and accurately given enough focused practice) I can recommend some easy outs that work 100% of the time at least 50% of the time in zbrush to get you there without much hassle and that’s under Polygroups menu and group by normals and group front. Most of the time to establish a quick blocked out polygroup to do something like protect backfaces you can group front in one button click. Turn your model around and ctrl+shift+click the back facing polygroup and hide it then group visible the front facing part and then you can hide your back facing part so easily, really no thinking required.
Stuff like that becomes natural after awhile, really much of the softwares functionality is based on a masking/polygrouping workflow and is just designed that way, and any hassle that appears to be there is kind of an illusion as they’ve thought of almost everything to help ease of life, just gotta know what all the things do and where to find them and whatnot. Which is the same with learning any software really.