This tutorial is based on the works done for the 3d rendered film Deep dreams
by the author Dan Tabonet.
First, in Blender, lets create a horizontal plane (go to top view [Numpad 7] and clik Add>Mesh>Plane). Press the S-key to scale it to nearly fill the view and then left click. In edit mode, press the F9-key to subdivide it, say 5 times, then deselect all by pressing the A-key. Press the B-key twice to obtain the Brush Selection tool. Use the mouse wheel to adjust the size of the brush until it's about the size of a face, like in Figure1.
Using the left mouse button, draw lines randomly on the mesh, selecting what will be the hollow parts of the rift. Don't make them too large. You should obtain something like in Figure2 (Top view). Finish by right clicking -once only!
Pressing the numpad 1 or 3-keys (front and side view, respectively) will allow you to see your plane in a lateral view. Then, turning proportional editing off, move the newly selected vértices a little above the others, for instance at a distance of 5 to 10 times the size of an edge, like in Figure3.
Exit the Edit mode by pressing the Tab-key. In the Multires Panel,press Add Level once, then Apply Multires. (tutor001.blend), Figure4.
Return to Edit mode. To reduce the number of selected points to move left's press the Control-Menus keys (numpad subtraction sign ".") You can now push these more deeply above the others again like in Figure5.
Now in object mode (Tab-key), in the Modifier panel add a Decimate modifier of a ratio like 0.3 and Apply. Do not go too low and alter the shape too much. (tutor002.blend) and Figure6.
Now toggle to Sculpt mode. In Multires Panel add 1 Level. Don't apply for now. In the Sculpt Panels set Brush to Inflate, Shape to Add, Size to 50, and Strength to 25 with Symmetry off.
You can now use the middle mouse button place the perspective view (orthogonal for instance by pressing the numpad 5-key) to allow you to draw in the regions of the rift which are in the rounded borders to make these look more like Figure7. (tutor003.blend)
You can now Apply Multires when sculpting is done in different points of view, until you are satisfied. An Auto Smooth of less than 30 degrees in the Mesh panel applied with a Set Smooth in the Link and Materials Panel will make the rocks look more realistic.
In Vertex paint Mode, you can set a greeny-blue colour for vertex points, and the excellent Self shadow VCols script, faquíng ambient occlusion can be applied twice, to make the deeper sides be darker. If you try to paint in vertex mode, use it VERY sparingly to keep realism on your scene. Last notes on the materials:
The material used for the rift must then be set with the VCol Paint button ON to see the different vertex colour modifications made before. You alos need to set the material Specularity very low: 0 would be good enough.
Here it is: the final render in Figure9.
If the lighting in your scene is like in the previous tutorial about caustics, you will get something that blend-fishes will be glad to swim in!
by Dan Tabonet