Animating spline control points?

[AJLynn]

I'm really new at C4D but I think it must be better for what I'm trying to do than Max (and I'm trying to learn it better), but I'm stuck, can anybody help?

 

I've got a spline that I've extruded to make a NURBS representing a structural member. I want to have it repeated in a line every 8 ft, while two of the control points of the spline move along two more splines being used as paths, so I think what I want is to animate it and use something like Max's Snapshot to freeze a copy at each frame, as the whole thing moves at 8 ft per frame in the Z direction, and the control points are at the point on their respective splines, which are in the YZ plane, where Z is constrained to the Z value of any of the other control points.

 

I've read through the tutorials and they make me believe this should be possible, but I can't figure out how to put the control point on the spline or how to do the "snapshot". Any tips would be appreciated.

[Frosty]

not exactely sure i understand what you are trying to do. could you post a sketch?

 

it sounds to me like you simply want to animate the points of a spline...very easy. Turn on Point Level Animation (grid of orange dots on your time bar) and animate the desired points with key frames.

 

I really dont understand what you mean by "snapshot".

[AJLynn]

Steve-

 

Thanks, I didn't realize there was a point-level animation button. Here's what I was trying to make:

 

 

I ended up doing it manually by duplicating then moving points, but I'd like to work out a better technique since this is likely to get more complicated.

 

The wavy spline running down the center is the path I wanted the center part of the ribs (which are roof beams) to conform to. My original thought was to have two of these splines (the top and bottom of the rib each have one control point) and fix the Y value of the point on the rib to the Y value on the path spline where the Z value is the same (I'm assuming I can figure out a way to do this in Xpresso), then animate it so the rib moved at 8 ft per frame, and "snapshot" the rib at each frame - then if I put all the "snapshots" together, I'd have all the ribs.

 

I'd like to be able to do this model again using more paths to control more points of the rib's geometry, and be able to make adjustments to the paths and recreate the roof without having to manually change all the ribs. Also the animation method would let me adjust the length of the roof and the spacing of the ribs pretty easily, but maybe the better way to do it is to make a bunch of duplicate ribs and do the spline snaps and not worry about animating.

 

The three spines running through the ribs are sweep NURBS - the center one is the path that the rib changes are based on, the other two are copies edited manually.

 

Any thoughts? Am I on the right track? I know this is all a bit kludgy but this is the first thing I've tried to make in C4D But I'm finding that the Maxon people seem to think a lot like I do, and I think when I learn more of these functions C4D will make a lot of sense to me.

[Frosty]

Reminds me a lot of Greg Lynn, as I expected it would. Glad to see you are using C4D for experimental design work.

 

I may take you on a tangent that is not what you were thinking....this may also spur a few neww design ideias for you.

 

1) Sweep nurbs can have two path splines. Spline A is the path and spline B is a deformer, both can be animated with point level animation (PLA). Your truss/beam spline could then be swept down a path and deformed by a second path creating an undulated derivative form much as you have already created.

 

2) Nurbs themselves can be animated. The growth factor, twist and scale of the sweep nurbs can be keyframed. The result would be an object that could "grow" down the sweep path while rotating and scaling up or down.

 

3) Booleans can act upon nurbs. If you modelled the negative space of your truss spacing (the voids) with cubic shapes, a boolean could cut out the openings as the sweep nurb grows along the sweep path.