Ya know..you sure got yourself a little gem of a program here.

This is the start of something really unique in the 3D arena.

Thanks alot for the tip. I'm entered into the CG Talk competition. So I'll probably be back for more help.

-DjD-

EDIT:

It would be nice to have an option to only displacement curve along one axis when projecting it onto a surface. Currently, when the curve is projected, it deforms. An option to maintain its profile and only displace it on one axis instead of two would be nice.

> It would be nice to have an option to only displacement curve along one axis
> when projecting it onto a surface. Currently, when the curve is projected,
> it deforms. An option to maintain its profile and only displace it on one axis
> instead of two would be nice.

Hi Twinsnakes, I'm not quite following this, could you please show an example of what you mean?

Projection should be happening along just one axis already - like in the crown example above when you do a boolean with a planar curve, the curve is projected just in one direction perpendicular to the plane of the curve.

So for example if you switch to the front view, the silhouette of the solid crown pieces line right up with the outline of the club curve.

If you are seeing something deform differently than that, it might be a bug...

- Michael

Well, I think the opposite. I shouldnt be able to line up the curve with the projected curve by looking at it along the projection axis.

As an experiment. I created a cube, then a unit circle curve. I rotate the curve 45 degrees then projected it onto edge of the cube. I then trimmed the circle curve in half, moved it to the edge of the cube, and finally rotated each half into place.

The highlighted portion of the image is my manual projection. The un-highlighted portion is what moi currently does.



I'm thinking the projection should act like the curve is a sticker, and should place it on the surface, just like if I was putting a bumper sticker on the bumper of my car....The sticker should'nt scale but only displace.

And that's why I asked for help. I layed down a club curve, but it looked stretched when I projected it for my crown.

Hi TwinSnakes, well the projection in your example would function like this - starting with a cube and a 45 degree angled circle:



The way the projection currently works is equivalent to the circle being extruded out:




You can see here where the extruded circle intersects with the cube - that's the resulting curves that you currently get.

This is sort of the regular way that projection works - I mean if you had an actual movie projector lined up in that same direction and the movie projector was showing a picture of a circle, you would get the same kind of shape there.


The way you're describing sounds sort of more like a physics based collision type thing like if the curve was made of stiff wire and was moving along that direction and then slammed into the cube and kind of wrapped around it... Unfortunately I don't have anything that will calculate something like that right now, it would be pretty difficult to make that.

> And that's why I asked for help. I layed down a club curve, but it
> looked stretched when I projected it for my crown.

If you can post your .3dm model file with the stretched curves in it, I might be able to give you some ideas...

- Michael

That's a great suggestion none the less - as much as I use projection, I understand it (just as Michael explained it) BUT I have to admit, I've often thought to myself that the resultant projection is "distorted" compared to what I'd really like at times...

It would be nice to have an option like this in the future - I'm not even sure what you'd call it? "Rigid Projection"??

-Will

Thanks Michael. I feel your pain. And sorry if in my post I sounded a like a lil jerk and a whiner.

But, yeah it probably is a rigid projection. And I looked at the javascript, and I can follow it pretty much.

I think you already have the tools we need. We'd need to project a point along an axis and intersect with a surface, we need to be able to calculate the distance between two points on a curve, and we need to be able to constrain by a 3D distance.

It might take a while for the script to process, but, I think it's a great feature and worth a look.

Hi TwinSnakes,

> and we need to be able to constrain by a 3D distance.

This one is the tricky part - on a wavy surface the constraint won't be just by a direct 3D distance between points, it would be by the distance traveled while hugging the surface, kind of like the length traveled by an ant walking along the surface...

On a cube with planar surfaces, everything is a lot easier... For working with just any surface at all things get way more complicated.

On top of this I see a lot of other difficulties - there would be cases where the rigid curve would actually not completely follow along a surface to maintain its same length. Like imagine a pocketed surface like a golf ball - if you try to apply a bumper sticker to a golf ball, the sticker is not going to completely hug along the entire surface of the golf ball, it won't touch the surface when it goes over one of the dimples. So just walking along the surface directly won't really give the proper result.

Also imagine taking the bumper sticker and trying to wrap it around the eraser end of a pencil - the sticker will kind of gather up and bunch together...

It seems like a pretty difficult problem.

- Michael