In this tutorial I will show you the basics of using the Poly-Build Tool and how to use it for retopology.
Poly Build Tool Basics
The poly build tool is useful if you want to make meshes on the fly and it is also useful for retopology
Tab into Edit Mode and delete the cube
Select the poly build tool and while holding CTRL, left-click anywhere on the grid and make four vertices
Select all the vertices and fill them (F)
As you touch the edges you will see a blue highlight color which indicates where you can make more faces
If you click in the middle of an edge and drag out, you can make a new face
If you click on a vertex and drag it out, you can make a triangular face
If you hold down CTRL and left-click away from an edge, you can make a new triangular face
Retopology Basics
The Poly Build Tool is very useful for retopology
Tab into object mode, add a monkey (Suzanne)
Using CTRL + 2, add a Subsurface Modifier
Right-click on the object and choose shade auto smooth
Add a Plane and rotate it around the X-Axis by 90-degrees
Scale and move the plane to it sits on the right-side of Suzanne’s forehead
Apply all of the transforms with CTRL + A
Add a mirror modifier and turn on clipping
In edit mode, turn on snap mode and choose “face project” under snapping and turn on “align rotation to target”
If I move the face, you can see it snapping to Suzanne
If I move the plane along the X-Axis, the two sides will snap together
Add a shrink wrap modifier with Suzanne as the target
For the wrap method, choose “project” and the snap mode should be “above surface”
For the axis, choose both positive and negative
I will increase the offset until I can see it above the surface
Under the overlays menu, I turn on face orientation to make sure all the normals are facing the right way
NOTE: If anything is red, select the red faces and using ALT + N, flip the normals
Also, if I turn on the cage, I can more easily see all of the vertices
Under the viewport shading options, change the color to “random” – this will make it much easier to see the planes on top of the object
Now all I need to do is select an edge and begin adding faces
I can also add an edge loop using CTRL + R to help the faces cover the object properly
I can switch to the select box tool and select a couple vertices, and use the M-key to merge the vertices at the center
Once you are done, open the merge menu using the M-key and choose “merge by distance” to remove any double-vertices
Then tab into object mode and apply the modifiers using CTRL + A