Flow on Revolved Surface

 From:  Michael Gibson
4549.2 In reply to 4549.1 
Hi Mike, yup you can actually use any surface as the base surface - it doesn't have to be a plane although mapping from a plane as the base tends to be the most simple one.

But the way Flow works is every point that is evaluated on the base object is dropped to the closest point on the surface. That then gives a UV location and an offset distance - then that same UV and offset distance is evaluated on the target surface.

You may have some difficulty with using revolves in this particular way though because of the compression in UV space that happens as you near the pole area. Possibly the new "Projective" option in the next v3 beta would be easier to do that kind of thing that you're showing. Also as a side note, when the new "Projective" option is enabled there will also be a "Straight" option that will do the kind of shaping that you had asked about a while ago where the shaping is constrained in one direction. It turned out to be a good fit with that option since in that mode there is a particular direction set up for projection already which could be used without any extra picking required. When that option is set the result of the projection will expand like an extrusion rather than like an offset.

> In this beta edition there is a problem with the flow result curves and
> surfaces "rippling" as the distance increases relative to some point of origin.
> This is an issue that I think Michael said he was working on for the next beta release.
> I tried the telephone chord spiral along a path thing and got the same strange
> ripple that increase in severity more to one end.

Are you talking about using base curve to target curve flow here? There is a bug right now where curve to curve flow (meaning using curve backbones rather than surface backbones) doesn't work properly unless both curves are flat in the world X/Y plane. If the curves are in some other orientation like standing up vertically you'll get that weird rippling effect. I've been working on fixing that just recently here and almost have it tracked down.

But for now lay both your base curve and target curve down in the world x/y plane and it should behave better.

> Also - Flow is sloooooooooow.... eesh. My goal was to make a speaker grill
> with well placed holes and other detail, as such would be done if a metal
> sheet of grill metal was stamped into a shape.

Yeah basically every single surface and edge in the model is reconstructed with a new refitted version, and it goes in and refines each of those rebuilt surfaces until it is within a good tolerance.

If you have a complex model with a whole lot of little surface pieces in it it may take a while to crunch through it all.

You can reduce the amount of time taken by reducing the number of surfaces in the model that you are deforming.

> BTW, Michael, I thought it was cute when my brother was looking at the
> Task Manager's Performance graphs on the work PC - while I was working
> with MoI, and asked me why only one of the cores was the only one
> working.... Well, someday. ;-)

Unfortunately things that are coded in the most straightforward manner only work with one core - it takes a considerable amount of special work and special attention to make an algorithm work well with multiple cores, it doesn't just happen on its own.

Flow could be a good candidate for using multiple cores in the future at some point though. In the current v3 time frame I'm much more focused on just getting it to generate a good result.

- Michael