Sphere Sweep, Canal Surface
All  1-2  3-7

Previous
Next
 From:  bemfarmer
9755.3 In reply to 9755.2 
Hi Wayne.
Right now it is intended to do a sphere sweep along a curve.
This can be different than just a circle sweep. In other cases, MoI already can do such things as Pipes, with circle sweep.

Reuleaux modWedge will be a very simple example, to be trimmed with the Reuleaux Tetrahedron sides.

I'll post more, as time allows.

- Brian

EDITED: 6 Apr 2020 by BEMFARMER

  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  bemfarmer
9755.4 
I wrote a canal surface/sphere sweep script, but it did not work.
MoI did not like my vector math, which was likely due to my error(S). :-)
It is hard to understand the vector/scalar formulas in various math papers. Notations vary.

I'll revisit the faulty script, but first, have reverted to a special case of the spheres/envelope being tangent to the plane z = 0.
For this simple case, the characteristic circles for the modWedge can be manually built in MoI4, say for 21 points, by using tangents and mirror and circle factory and Loft.
I'm slowly working on a simple script version...
The sphere sweep is often NOT the same as a circle sweep.
(The resulting modWedge does not like to boolean union or trim with the Reuleaux tetrahedron, which is another story.)

The new MoI4beta curve methods, such as crv.dropPoint( pt ),
and crv.evaluateTangent( t, 2 ) are very useful.

So: Is the second derivative at NURBS parameter "t" associated with point on the curve <<<Equivalent>>> to the Normal at the point ?
(un_normalized) ?

- Brian

EDITED: 25 Apr 2020 by BEMFARMER

  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  Michael Gibson
9755.5 In reply to 9755.4 
Hi Brian,

> So: Is the second derivative at NURBS parameter "t" associated with point on the curve
> <<<Equivalent>>> to the Normal at the point ?

No, but they are related. The curvature vector is calculated from the first and second derivative.


- Michael
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  bemfarmer
9755.6 In reply to 9755.5 
Thank's Michael,

Back to vector math calculus class for me :-)

- Brian
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
 From:  bemfarmer
9755.7 
Todays idea is to perform a sphere sweep on a curve, using Flow.

Unwrap the curve.
Sphere radii vary along the arc length.
The envelope, for the unwrapped curve (straight line), is a surface of revolution.
The rate of change of the radii equation with arclength to be limited by ?
To get the planar curve to revolve... ???

- Brian

EDITED: 18 May 2021 by BEMFARMER

  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged
 

Reply to All Reply to All

 

 
 
Show messages: All  1-2  3-7