Polygroups are a useful way of grouping certain areas of a single subtool, to make selecting and working on them easier.
You can hide/unhide polygroups, mask by polygroup, sculpt on them and assign individual materials to them, making them a very useful organisational tool. They can also be used to influence ZRemesher, so setting up polygroups can help get a better retopolgy.
BASICS
When you import a model from another package, it will be brought in as one single polygroup. Press Shift + F or press the PolyF button (to the right of the canvas) to activate polyframe view, which is like a wireframe grid running over the surface of your model.
Ctrl + W will convert any visible area to a single polygroup. If the model is masked, only the masked area will be polygrouped. – it will change colour to signify being part of a new group. Alternatively, open the Polygroup palette and click the Group Masked button.
NB: The From Masking button is not recommended as it will not preserve previous polygroups.
To remove polygroups, just mask the whole object and press Ctrl +W to make one single Polygroup again.
The Auto Groups option in the Polygroup Palette will attempt to automatically split your tool into groups.
‘Merge Similar Groups’ can be clicked to add similar objects into a similar polygroup- eg if tyres on a car are 4 repeated elements, they will be merged into one polygroup.
CLEANING UP MASK SELECTIONS
Since polygroups are created via masks, here are some masking tips:
- To mask, hold Ctrl then paint on your model, this will darken the selected area.
- The Mask Lasso brush is much better at selecting geometry than the basic rect selection.
- There is a masking palette, with useful options including Grow Mask to make it extend outwards, Blur Mask and Sharpen Mask to adjust your mask edges.
(Blurring, then sharpening your selection is often a good way to get crisp edgeloop selections)
To select tight geometry (such as a single finger in a curled fist) Select the move tool, press Ctrl +L Click and drag your mouse over the element you want to mask. This will mask it whilst stopping at the border.
CLEANING UP POLYGROUP EDGES
Depending on your subdivision level, the borders of polygroups can look quite ragged. If you go to the Geometry palette and click the Group Loops button you can smooth the boundaries of your groups. The options nearby will help you refine this smoothing process. NB: This will both create new polygon geometry, AND create a new, very narrow polygroup along the seam, so USE WITH CAUTION.
USEFUL OPTIONS
The polygroups tab has a number of useful function buttons:
Split Groups – This option in the Subtool palette will allow you to split a tool into subtools, based on how it is divided into polygroups.
Group Visible: This option will combine all visible polygroups into one.
SHOWING/HIDING/DELETING GEOMETRY BY POLYGROUPS
- Ctrl + Shift + Click on a poly group to hide other groups on that subtool.
- Click on it again to hide it and show all the others.
Click on it once more to bring everything back.
- Alternatively, Ctrl + Shift + Click on an empty space to bring back all poly groups.
- Keep Holding Ctrl + Shift + Click on additional groups to now hide them, along with the original
- Ctrl + Shift + Drag Click on an empty space to invert visible/hidden groups
To delete parts of your mesh, hide them then go to Geometry > Modify Topology > Delete Hidden.
Z REMESHER TIPS
When using ZRemesher to clean up your topology, making polygroups and selecting the Keep Groups button in the palette will maintain existing polygroups, and help define the edgeflow of the remesh, based on group borders.