In Modeler, the retopology tools are based on Houdini’s standard TopoBuild tool, but with a key difference in how the modes are activated. In Houdini, TopoBuild modes are triggered using the Shift+1...6 hotkeys. In Modeler, all retopology modes are conveniently grouped in the Topo radial menu. This allows you to activate any mode directly from the menu without needing to first activate TopoBuild and then select a mode. If the TopoBuild node hasn’t been created yet, activating one of the Build, Slide, Split, Brush, or Smooth modes from the menu will automatically create the node.

How to Retopologize in Modeler:

• Open the Topo radial menu using Alt+X and check the Topo checkbox.
  • The tool will prompt you to select a high-poly object. After selecting, it will temporarily hide the object and ask you to choose the object on which you will perform retopology.
  • If you need to create a new object for retopology, simply press Enter without selecting anything.
  • The viewport settings will adjust to better display polygons over the high-poly model.
• Use the tools from the menu: Build, Split, Slide, Brush, Smooth, and Draw Patch.
• You can also use other modeling tools, but to project the result onto the high-poly model, use the Project tool from the Topo menu.
• To finish retopology, activate Topo again to reset the viewport settings and stop accounting for the high-poly object in further modeling actions.

Tools in the Topo Menu:

• Topo — Activates retopology mode.
• Project — Projects all current geometry onto the high-poly object.
• Build, Slide, Split, Brush, Smooth — Standard retopology tools using the TopoBuild node.
• Draw Patch — A tool for creating patches, allowing you to intuitively "wrap" the high-poly model with polygons, saving time and eliminating the need to manually create multiple polygons.

PolyPen

The PolyPen tool offers powerful mesh editing capabilities, making it a great addition to the retopology process.