NURBS and 'locking down' vertices

[DALucy]

Hi,

I'm trying to add a curve to the top surface of a rectangular shape (similar to the NURBS tutorial). I have moved some of the middle vertices upwards and selected Move vertex only. This still lifts the edges of my rectangle slightly so it no longer joins with the vertical faces and won't form a solid. Is there a way to 'lock down' some vertices where they join other faces so you don't get this?

Thanks in advance!

[graham75]

Would increasing the vertex weight to 100 (max) achieve this? Anyone else know?

[graham75]

I just tried this on a NURBS surface... changing the weight doesn't work.

However, when creating a NURBS curve, you can modify the vertex using the Change Vertex Mode option in the 3D Reshape Tool, so that it becomes a Corner Point rather than a Bezier Control Point. But that only helps you if you want that point to be a corner.

Unfortunately, unless someone else has a solution, you would need to redraw this using multiple shapes and your Modify drafting tools.

Edited August 1, 2008 by graham75

[Benson Shaw]

Here is one exercise which should get what you want.

Create Rectangle

Modify/Convert to Nurbs

3DModeling/PowerPack/Convert Curve to Surface

In OIP check the Untrim box. This creates surface with U and V vertices.

In OIP increase degree of U and V vertices to 2 which creates a middle vertex.

Select Vertex Only in the move field.

Navigate to the middle vertex with the OIP arrows.

Increase z dimension of mid vertex. The perimeter vertices do no move. Increase weight of middle vertex to make the mound more pronounced.

This round topped rectangle can be combined with an extruded rectangle of same base with Add Solids command.

-B

Edited August 2, 2008 by Benson Shaw