1) Duplicate a bit of road
Enable Performance Mode, go into Edit mode, select and edge from your existing segment of road and duplicate it using SHIFT+D:
Resize it by using double G on one select vertex and slide it around:
2) Subdivide the nearby edge
Select the nearby edge from the road segment and subdivide it, double G move the newly created vert to meet the position of the new segment’s vertices like so:
3) Merge the two road segments
Select the new edge and bring it closer to the existing road segment and make both the Road mesh and Support mesh merge with themselves like so:
4) Change the width of the road
Select the vertex on the right end of the newly created edge.
Hit N if the N panel isn’t open in the 3D viewport, if so, head to the Item tab like so:
Locate the Vertex Data sliders.
Bevel Weight is responsible for the width of the Support Mesh for each vertex.
Vertex Crease is responsible for the width of the Road Mesh for each vertex.
Let’s set both of them to 0 for the selected vertex like so:
Now, let’s bring this vertex closer to the side of the road from the other road segment and let’s try to make both Road mesh and Support mesh merge into a triangle for that generated face like so:
5) Extend the extraction
Let’s select the other vertex from the extraction edge and extrude it using E like so:
Let’s subdivide both these edges now:
And double G slide both newly created verts to be positioned like this, as you can see, we want them to merge the support but not the road where they meet:
Let’s TAB out of Edit mode and disable Performance Mode:
Congratulations, you created your first extraction!
Important Things to Remember:
1) Vertices position on Intersections
One thing to remember, is that on intersections, especially those elongated ones like we’ve created here, the subdivision of the Path Mesh edges has to match on both parts of the intersection.
Here’s an example of what to NOT do:
And here’s an example of what to do:
We want both edges following the intersection to have roughly the same length:
Otherwise, the intersection will stretch to one of both sides after subdivision, and this could result in multiple problems.