In Blender’s overall workflow, which includes modeling, sculpting and animation, a major missing piece is retopology.
No Retopology?
As part of the overall focus of sculpting improvements, this is an area we should address.
After talking to @Pablo Dobarro (pablodp606), we agreed to set up this document to help define how we should approach this from a UI and workflow perspective.
Issues
Display
One of the major issues currently, is that we have no great built-in way to display your retopology mesh on top of a high res sculpt.
By default, your mesh will intersect with the high res sculpt:
You can enable In Front, but that makes the *whole* retopo mesh display on top of the reference, also the parts that should be occluded:
Not only is it confusing to set it up, but the result is sub-par.
What we really want is something more like this:
The occlusion is correct and the faces aren't intersecting. The retopology mesh is half transparent so you can see the underlying detail.
Snapping
There are a few issues with snapping:
- You have to enable some very specific settings that are not obvious
- There's no way to only snap to a certain object or Collection - you can easily accidentally snap to an item somewhere in the background
- Snapping is only active while you are using any of the transform tools. If you for eg subdivide an edge, those edges aren't snapped to the source. Users then have to select those items and move them a bit to snap
- Some users use the Shrink-wrap modifier, but this has issues with the mesh is too far away from the source - the projection becomes unpredictable
Tools
Compared to more dedicated solutions for retopology, Blender is lacking many basics. Things like drawing a 'strip' of quads, or defining a patch of quads. Or tools to automatically handle appendages just by drawing lines along it. Or even just a basic tool for 'drawing' topology onto the source mesh, which is then auto-filled with quads.
Setup
To get started with retopology in Blender, so many settings and display options have to be toggled and set by the user, that there exists entire tutorials on how to do this. The needed steps and settings are not only non-obvious, but also take time and focus away from the task at hand.
Solutions
Display
Add a Retopology overlay display option, replacing the current Hidden Wire Edit mode display
Snapping
Add a Retopology snapping option, which allows snapping to self while also projecting onto source, and snaps the current selection.
Tools
We can start by improving certain tools, such as Poly Build, and also add more edit mode tools. Even though they may be more constrained inside Edit Mode, we can try to use this as a test-case for more advanced gizmos and tools in general
Other examples of the kinds of tools we could add are things like:
A tool that lets users define a patch with handles, which is automatically filled with quads:
A tool that would let users draw a line, which then becomes a strip of evenly sized quads
A tool that would allow users to nudge around points with falloff, like a brush:
Addons
We probably don’t expect to provide a full and comprehensive set of retopology tools, at least initially. For this reason, addon developers could provide extra tools that integrate with the toolbar and tool system.
