View Full Version : animated extrusions

04-23-2004, 04:44 PM
A friend asked for a hand with this problem, and I can't think of a really efficient solution...

We're looking for an easy way to animate an extrusion on a complex curve -- essentially to make a rope grow or slide along to form a knot. Of course I can do this with extrusions and morph targets, but it takes a lot of targets to get it right, and if anyone wanted to do a lot of them, the time required becomes a problem.

Is there a way in LW that I am just not thinking of? Or is there a plugin that will do this? I had an ls called "grow" but it seems to be compatible only with older versions of the software...

Thx in advance...

04-23-2004, 06:49 PM
this tutorial inspired me to try what you are saying using spline guides:
here was my result:

I beveled the polygons out, morphed them in, animated the morph from 100% to 0% (back out), and used spline guide to get the desired shape.

04-24-2004, 06:43 AM
Thanks, I'll check that out!

Somebody in cgtalk suggested:

(Thanks Orkman)

Which I'm also trying out.


04-26-2004, 01:01 AM
hello, try this.... from an old post.... i cant remember who did this but thanks again....:D

04-26-2004, 06:45 AM
Hi Tony,

I think the growing vines tutorial is here www.mdarts.com. A really fast way is to use a clip map.
1. Make your knot (make sure you know how many segments it has)
2. Make a short straight tube with the same amount of segments
3. With the straight tube as the base use BKG to Morph to make the knot a morph of the tube.
4. Slap it over to layout and animate a half black half white image map along its length, cut and paste this into your clip map panel (object properties/render/clipmap) and switch off the image map in the surface textures panel
5. Apply the morph from frame 0 and tada!!! animating rope

see mov
sorry it's so basic but tempus fugit (I think!)

Now this doesn't take into account the inside of the rope. for that you need to check out the t-rex clipmapping tut at the above website or perhaps look at shift/boolean (unless you are on a Mac)

also you could fiddle with Fi's Bezier Bend or Hoser (worley labs)

Hope this helps



and thanks for all of your tuts as well Tony

04-27-2004, 05:51 AM
Thanks all for the helpful suggestions. I ended up using the method described below -- it is very fast (once you get your head around it -- it's kind of a wierd work flow) and easy to edit -- and has the big advantage of correctly morphing along even complex paths, with a minumum of effort.

(Thanks to PixelRanger and SplineGod)


PixelRanger had made this suggestion in another thread:
"Make a skelegon chain in modeler looking like your logo. The skelegon chain should start from 0,0,0, and start off towards +z.
Now make a multisegmented (in the z axis at least) box.
Make a morph. In the morph, stretch the box in the z axis towards +z.
Save object, and go to Layout.
Open object and convert skelegons to bones.
Open the Spreadsheet and select the Bone Property Basic bank. Reset all rest rotations for all the bones to 0.
Press "B" and "p" to get the property panel for the object's bones.
Check the "Use morphed positions" box.
Select the object and add the morph mixer.
Now, when you slide the morph slider, you'll see that the box "extrudes" along the skelegons.

tip: Under the construct tab there's a Convert group with a "Make Skelegon" button. If you have made your original logo from a curve, you can convert this curve to a polygon chain with this button.

If the curve has too few control points, so that the skelegon chain is jerky, just freeze the curve, kill the poly, lasso-select all the points, and hit "ctrl-p" or "Make curve". There you have your smooth skelegon chain."

This seems to work fine even when multiple bone chains and doing an animated magic bevel kind of thing. What I did find is that I had to leave the rest heading the same on the first bone of each chain to get it to work.

Again its a workaround but it might work.


04-27-2004, 08:22 AM

check out this thread. i had the same problem as you, and i can only recommend the plug-in that was suggested to me at that time. it worked perfectly, with very little effort, and great control.

if you need any further help with this, just lpost your questions here.

have fun!

04-27-2004, 08:28 AM
... and if you do download the plug-in, i also posted some instructions on how to use it, for another user, afterwards.