How to change the topology correctly

[JekSun97]

I want to change the topology of the base mesh, for example adding a couple more arms, what is the correct way to do this?

[joepal1976]

The short answer is that you don't. The number of verts in the basemesh are fixed. You can move them around, but adding extra arms is probably beyond what you have enough verts for.

Luckily you don't need to. You can add an alternative topology ("proxy mesh"). See https://static.makehumancommunity.org/mpfb/docs/assets/concept_proxymeshes.html for background info. These are modeled using the makeclothes toolset. There is also the possibility to add a subrig to animate parts of it, although the UX for this might not be great.

So my hint is to start thinking of the shape as clothes put on the base mesh rather than a change to the base mesh.

[JekSun97]

So if you create a zombie without one arm, there are no options left, right?

[joepal1976]

The process would be mostly the same: Create clothes or a proxy with a delete group hiding the arm you don't want to be visible.