Cancel
Showing results for 
Search instead for 
Did you mean: 

manipulators of Bridge Curve

Valued Contributor
Valued Contributor
Alias has a command Blend Curve, almost an equivalent to Bridge Curve in NX. It has two manipulators: a circular one and a rectangular one.
 
  • The rectangular one is basically equal to tangent magnitude in NX, and dragging it could move both the pole 2 and pole 3 simultaneously. 
  • The circular one seems to be unique. Dragging it could move only pole 3 and does not affect pole 2. This seems to be useful in case of adjusting certain pole structures.
 
Do I miss a manipulator in Bridge Curve similar to the circular manipulator in Alias' Blend Curve?
 
Thanks!
 
Image.pngBlend Curve in Alias
pole 1: left
pole 2: middle
pole 3: right
11 REPLIES

Re: manipulators of Bridge Curve

Experimenter
Experimenter

Circular Blend Curve works quite well also

Capture.JPG

Re: manipulators of Bridge Curve

Valued Contributor
Valued Contributor

Hi @Fixture_guy   Thanks! What I mean is about controlling the poles of a G2 blend curve.

Re: manipulators of Bridge Curve

Experimenter
Experimenter

By double clicking the created bridge curve will bring up studio spline and it has many curve manipulations

Capture.JPG

Re: manipulators of Bridge Curve

Valued Contributor
Valued Contributor

Hi @Fixture_guy

 

Are you sure that double clicking a Bridge Curve would bring up studio spline dialog box, not a Bridge Curve dialog box?

 

I think that you might mean extracting the Bridge Curve to get a Studio Spline.

 

I'm thinking about whether Bridge Curve provides manipulators for controlling pole 2 and pole 3 separately. Thanks!

Re: manipulators of Bridge Curve

Phenom
Phenom

@surfactant,

 

I didn't see anything in your link to the Alias tips that stated you have direct control over any poles (apparently called CVs in Alias) using the Blend Curve tool.  I believe those indicators are shape controls, which indirectly control the pole position based on the continuity assigned to the curve and how the manipulators are positioned.  I don't see this being (possibly) any different than using Bridge Curve and rather than using Tangent Magnitude, using Depth and Skew options but it's hard to guess since there wasn't a specific example showing how the Alias manipulators could be used.

 

The Bridge Curve Depth controls how sharp or flat the Bridge Curve will be and Skew controls to which side the Bridge Curve will lean.  Changing either of these settings "should" indirectly manipulate the poles (CVs) on the Bridge Curve because you're increasing and decreasing tangency or curvature, which means you're moving the poles (CVs) as well because the curve shape is changing.  The poles will only move along the tangency (angle) because if they were to move to the right or left side of the parent curves, this would break the continuity.  You can see this if you turn on Show Poles while you're creating the Bridge Curve.  I would assume the Alias manipulators would behave the same way.

 

You could do the same things using Studio Spline, but it's usually a bit simpler with Bridge Curve.

-Tim

Re: manipulators of Bridge Curve

Valued Contributor
Valued Contributor

Hi @TimF   Thank you for the long reply!

 

Bridge Curve has two modes of shape control: 

 

  1. Tangent Magnitude for the start and Tangent Magnitude for the end
  2. Depth and Skew

For each modes, there are 2 manipulators for the shape control.

 

Alias' Blend Curve has two manipulators (a rectangular box and a circular box) for both the start and the end. Therefore it has 2*2 manipulators for shape control. And for a degree 5 blend curve, each pole can be separately moved.

 

Image.png

Re: manipulators of Bridge Curve

Valued Contributor
Valued Contributor

Hi @TimF   Please refer to Change the tangent direction at a blend point. Thanks!

 

aaa.jpg

Re: manipulators of Bridge Curve

Phenom
Phenom

@surfactant,

 

Do you have Alias installed?

 

If you wish to have that sort of control, use Studio Spline like I stated earlier.  Set Studio Spline to By Poles, G2 at each end and 5 degree, single segment.  You can then either infer the contuity or control it via Specify Constraints (manipulators).

 

Inferred G1, G2 or G3 will "auto align" the poles for the optimal shape and lock them into the same alignment/angle as the parent curve on that side.  Using MB3 -> Specify Constraints on the start or end pole will allow you to deviate from the "optimal" shape.  Play with it a bit to see what I mean regarding the Specify Constraints.  The manipulator route will not update if you change the parent curves as far as G1-G3 continuities....you will have to respecify those.

-Tim

Re: manipulators of Bridge Curve

Valued Contributor
Valued Contributor

Hi @TimF   

 

I don't have access to Alias. I simply studied their official tutorials.

 

Your reply makes me realize that Studio Spline should be used for full control of pole structures and Bridge Curve is basically an easy version of Studio Spline. Thank you so much!