Wish: U/I change to adjustable blend curve

Sorry to bump an old thread but I’ve encountered this “issue” working with blend curves. It would be really nice if there were a way to numerically enter a factor to adjust the shape, I think it’s called Form Factor in Alias. It would make it easier to keep blend curves consistent across a model.

Be nice to see it in V7.


Sorry, we don’t use Alias so comparisons without specific details are pretty useless.

Can you please describe or show what problem you’re trying to solve so a non-Alias user can understand it?
Otherwise this request will remain ignored.


I’m not an Alias user either. I came across the term “Form Factor” in their online manual whilst searching for ways to adjust a blend curve in Rhino (Google often seems to throw up AD help docs). I thought it might be a mathematical term rather than specific to Alias, and therefore helpful to mention.

What it seems to do is allow you to control the position of blend curve CPs numerically, I’d guess using a ratio. As far as I know (and I could be wrong hence my searching) there isn’t a way to do this in Rhino.

The problem this would solve is one of consistency - in some cases I’d like my blend curves to have a similar shape. Being able to type in a value would be quicker and easier than manual adjustment.

Hello - We have this on the heap - currently it is part of a bug track item that is not visible to the public, but it is on the pile, I’ll split it out on its own.

RH-59345 Adjust blends numerically


1 Like

Thanks very much for the update, Pascal.

Hello Pascal,

if the “Form Factor” option gets added, I would like to propose a visible Indicator showing the resulting smallest radius and its location for each radius segment.

Filleting often is a safety requirement for head impact. It also is a manufaturing requirement as tooling will not be possible below certain values.

However predicting the resulting radius-value when building G2-fillets is difficult. This way the fillets can be adjusted until all requirements are met.

I would work this way:

“Form Factor” = 1 :no change, chordal CV distribution
“Form Factor” < 1 :flatter fillet
“Form Factor” > 1 :sharper fillet