Night Vision Goggles - NURBS

[clintonman]

I decided to follow a NURBS modeling tutorial for Maya, but using trueSpace. It will be a model of cartoon style night vision goggles. I started by follwing along doing the same thing as the instructor. He starts out by drawing curves on the surface of a head model and then skinning them to make a patch. I was able to follow along but it fell apart when I did the skinning step.

threeHandlesAtCornersCurves.jpg (14.97 KiB) Viewed 8567 times

The problem was the the instructor was using a different method to create the curves and so I had too many controls at the corners. He had 3 so I put 3.
So I figured I would use 1 control at each corner and the handles would act as the other 2 points of lesson.

[clintonman]

The second attempt I ended up using the workspace scripts to create the curves. There would be a control at each corner and it was easier for me to make the curves in workspace. I also reduced the number of profile curves of the eye opening to just 2. Before there were 4 curves. The result was better but still not right.

oneHandleAtCornersBentCurves.jpg (13.58 KiB) Viewed 8569 times

The corners are still too sharp and it looks like it's slopping downward.

[clintonman]

Third times the charm. I finally got the result I wanted by making the curve point handles line up in a straight line instead of bending. The control handles are straight and scaled down on size to get a corner.

oneHandleAtCornersStraightCurves.jpg (14.06 KiB) Viewed 8571 times

At this point I discovered a flaw in the workspace freeze transform script. I was getting strangely shaped curves when I exported from workspace/imported to modelspace. The curves came in properly after it was fixed. In the next step of the lesson the instructor does a lathe type action on a curve. Truespace can do this but converts it to a polyhedron object. I think I can simulate the same action with a new plugin. There is a version of loft surface in the SDK that seems to have more control than the button command. The idea is to use a circle as a loft path. We'll see how that goes.

Here is a pic of the final curve network for that part of the model. Created in workspace and exported to individual cob files and imported to modelspace. 3 of the 5 curves were used in the skinning shown.

[clintonman]

Lessons learned so far:

When skinning straight handles on the curves are better than bent handles.
A Maya cv curve is not the same as a bezier style curve.
When using the curve library for the first time it is thin and stuck to the side of the interface. If you insert a few curves and make the library shorter and then wider you can get access to the title bar and move it around.
The skin tool eats the curves in the process.
Loft can be used to simulate a revolve/lathe action, but it acts on the geometric center of the profile curve.

Bug in the freeze transform script(fixed)
Workspace curves are awkward in the LE because 3 nodes are needed for each curve. This needs to be cleaned up.
tsxPipeSurfConstruct from the SDK looks like loft but any point in space or along the curve can be set as the center of the profile.

[Draise]

This is an incredible read, and great process and progress! thanks Clinton, you're legend. I don't do too much NURB modeling, but when I do I'll keep all of this in mind! Thanks.

[v3rd3]

Thanks for sharing this clinton.

[DarkScythe]

nice clintonman... I have a hard time using nurbs in modelside good to see a step by step procedure.

[clintonman]

My first success with a NURBS lathe plugin. Image shows the result and the curves used to create the lathe. The circle and the second profile curve will be deleted in the final plugin. The command I found in the SDK made it looked like it would be easy to do a lathe plugin, but it was trickier than I thought. I have a working plugin that works in the z axis. I just have to get it working with the x and y axis and I'm done.

[Emmanuel]

A lathe tool for NURBS opens plenty of modelling technics.
I remember in page 208 of tS's User Manual a tutorial to create a glass using tS's NURBS. The tuto was teaching how to draw the profile of the curve (in NURBS), but when I came to generate the volume and lathe the profile, user was forced to convert the object in polyhedron... loosing all the softness of a NURBS curve ! It was evident that a NURBS version of the lathe tool was missing in the workflow...

It is fantastic that so many years after tS6 release, you Clinton finally complete the toolset ! clapclap !

[spacekdet]

There's always a workaround!
Hope this plugin makes things easier.
NURBS rock.