variable blends

[rr79]

Just wondering how people acheive variable blends on multiple edged lines? For example if you have a bowl whose outer edges is seperated in 6 segments, and you want to define a radius of .25 in the back and a raduis of .75 in the front of the bowl and have a contiunally decreasing radius though the sides which connect the front to back?

[John van Doorn]

Don't use multiple edges, but instead try to use splines before an extrude.
This way you will get one continuos edge which can be used to create a variable blend.


Goodluck,
John

[Gary L.]

Using create blend, select your first edge. Change type to variable radius. Fill in the start and end radius for this edge. Select the next edge in the chain and enter a start and end radius. Continue this until you complete the chain of edges.

Hint: Turn on labels at the top of the create blend dialog box to get on-screen feedback.

Gary

[Jim McKim]

Gary's suggestion seems to work fine for straight edges, but it didn't work when I tried creating variable blends along the inside edges of an L-shaped piece that has a radiused fillet in the inside corner. You can't create a blend on the first edge because it fails at the end that runs into the fillet. It doesn't seem to matter whether the fillet was created by extruding or by blending.
But, by misinterpreting Gary's message (I think), I accidentaly hit upon a solution: Use Create Blend/Constant Radius to blend all three edges (both legs of the L plus the fillet), then you can go back using Modify Blend/Variable Radius and change any of the three. You get some weird looking results if the end radius of one variable radius blend is different than the radius of the blend on the adjoining edge, but it works! The weirdness goes away when you modify the adjoining blend to adjust the radius for continuity. I successfully blended all the edges of one face of the L with variable blends. :D

[rr79]

Thank you for your suggestions. Does anyone think it would be useful to have a chain command linked to variable blend, such that you only had to define the start radius of the chain and the end radius of the chain? I realize working with a spline instead of a segemented curve would work, but there are times when you can not avoid having a segmented curve. Just my two cents.

[Jim McKim]

I think that would be a useful function. I don't really care about the actual radii at the intermediate intersections, only that it is smoothly continuous. The only way to do that currently is to interogate edge lengths and proportion the blend radii manually.

Will you submit this to CoCreate Support as an enhancement request?