At this point, when we look at the Gidiosaurus mesh, we realize that some detail in the model is still missing; for example, the lower teeth. In fact, we modeled the mouth closed and the lower teeth, enclosed in the upper mouth rim, weren't visible.
It's now time to add them; in fact, even though we have already done the unwrapping stage, it's still possible to modify the mesh further and also update the UV islands accordingly.
Start from the last Gidiosaurus_unwrap.blend file you saved:
- Press N to open the Properties 3D view sidepanel, and disable the Textured Solid item under the Shading subpanel.
- Click on the 11th scene layer button to reveal the Gidiosaurus_lowres object and select it; go into the Side view, zoom in to the head, and enter Edit Mode. Press the A key to select all the vertices of the mesh.
- Put the mouse pointer inside the UV/Image Editor, select all the UV vertices (again the A key), and pin them by pressing the P key; then deselect everything (the A key once more).
We can now start to add new teeth:
- Select the vertices of one lower tooth and press Shift + D to duplicate it; using the Transform Orientation widget set to Normal, scale it smaller, rotate and modify it a bit, and then move it in a new position along the mandible rim:
The new added tooth
- Repeat the process to create the bottom teeth row on the left-hand side of the mandible:
Adding the missing teeth
- Go out of the Edit Mode and put the 3D Cursor at the pivot point of the mesh (coincidentally, at the center of the scene), and then press the period key (.) to set the Pivot Point around the 3D Cursor.
- Press 1 on the numpad to go in the Front view, enter Edit Mode again, and select all the new teeth; press Shift + D to duplicate them, and then right-click; then, press Ctrl + M | X | Enter to mirror them on the x axis to the right-hand side of the mandible.
- Press Ctrl + N to recalculate the normals and go out of the Edit Mode:
The new teeth mirrored on the x axis
Now, we must adjust the rim of the mandible where we added the new teeth, in order to create the alveoli.
- Go back into the Edit Mode and start to add vertical edge-loops on the lower mouth rim, in order to create more geometry for the alveoli:
Adding new edge-loops
- Click on the Options tab under the Tool Shelf to the left-hand side of the 3D window and enable the X Mirror item under the Mesh Options subpanel.
- Tweak the vertices to create the alveoli around the new teeth; enable the Subdivision Surface modifier visibility during Edit Mode in order to have better feedback:
Modeling the alveoli
- Press Alt + S to scale the teeth vertices on their normals, in order to thicken them, and add edge-loops where needed to make the transition from the alveoli to inner mouth as natural as possible.
When you are done, it's time to update the unwrapped UV layer with the new modifications.
- In Edit Mode, first select the vertices of the new teeth. Because we made them by duplicating one of the already unwrapped fangs, the new teeth will share the same UV island. In the UV/Image Editor, press A to select all their UV vertices and Alt + P to unpin them, and then press E for a new unwrap.
- Scale the new teeth islands to 0.200, and then select the original teeth on the mesh; adjust the size and position of the new islands based on the old ones and then pin them.
- Now, switch to the Face selection mode and select the Gidiosaurus face; in the UV/Image Editor window, unpin all the vertices of its island (Alt + P), and then pin only the vertices of certain areas such as the eyes, nose, and upper outside edge-loop (P key).
With this method, the unwrap of all the new geometry gets recalculated together with the old one. Thanks to the pinned UV vertices, it will keep the previous size and position as much as possible. In the following image, you can see the face island before (left) and after (right):
The updated unwrap
Note that you need to recalculate the unwrap for all the islands involved in the mesh's modification, and then save the file.