In this tutorial we are going to make 4 different shapes of diamond. We will make material for them in VRay and finally render them.
Create a Cylinder. Make sure its Sides set to 16. Its Height and Width Could be change later by moving its vertices.
Convert the Cylinder geometry to Editable Poly and select its bottom vertices.
Click on Weld button and increase its amount until all the bottom vertices welded together.
In the Top view, same as the below photo make new cuts on the above surface. Follow from left to right. You can make new faces by Cut tool.
We need to cut more faces. In the blow photo, you can see the place of the new cuts with red lines..
Select middle vertices of the top surface.
Use Scale tool and from Top view scale the selected vertices same as below photo. You should scale them along X and Y axis. Now you can compare the result with blueprint of round diamond. We almost created the same lines.
While the top vertices are selected, move the up. You can use a reference photo for making the height of the diamond.
Follow the below photo and select the vertices that shown with red color.
Move them down to make straight line.