Question on the use of Flow

Next
 From:  chippwalters
7751.1 
Why is the flow not perfectly round? Instead it's elliptical.


File: https://altuit.cloud/web/dbpub/3D/flowQuestion.3dm

Issue:
  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:  BurrMan
7751.2 In reply to 7751.1 
Hey C Dub,
It is because of the disperate surface structures... Try this one....

  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
7751.3 In reply to 7751.1 
Hi Chipp - it's because Flow works on the "underlying surface" of the target surface, it shrinks down that surface to the UV bounding box of the trim curves, but it does not follow directly along trim curves, it follows the full surface beneath those trim curves.

When you do the boolean part, the surface that you are getting has trim curves on it that mark cut away areas.

You can get a better idea of what I'm talking about if you select the sphere part, then run ShrinkTrimmedSrf (http://moi3d.com/3.0/docs/moi_command_reference10.htm#shrinktrimmedsrf) , then turn on control points for the sphere fragment by using Edit > Show pts - you will then see the control points for the full underlying surface, which extends a ways past the boundaries on 2 sides, and if you select the trim boundaries and hit delete to untrim it you'll see the full surface that Flow is using and how it's longer in one direction than the other direction.

When you use a surfacing command like Loft, Sweep, or Network, those all build untrimmed surfaces as compared to using a boolean which makes trimmed surfaces.

EDIT: looks like Burr beat me to it! :)

- 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:  BurrMan
7751.4 In reply to 7751.2 
Here is a quick video:



So notice the point structure on the top surface when starting. That "box" type structure is the indication of a separate surface type. A type of analytical surface (Michael can correct the terminology)...

So first I shrink the underlying surface, then I actually added a point structure, which converts it to a regular NURBS BREP, then I just flatten IT to use as the base....

Burr

[EDIT] Sorry. Somehow cursor didn't get recorded so you will have to look harder... fixed it for future [EDIT]

EDITED: 4 Dec 2015 by BURRMAN

  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:  BurrMan
7751.5 In reply to 7751.3 
"""""""""EDIT: looks like Burr beat me to it! """""""""

Actually, untrimming the underlying surface is more elegant than my suggestion. I didn't think of that!
  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:  chippwalters
7751.6 
Thanks guys!

I updated my query video to add your suggestions. It worked. I understand I may have wanted to 'square up' all of the points in the base mesh, but it turned out just fine anyway. Much appreciated!



  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:  Frenchy Pilou (PILOU)
7751.7 In reply to 7751.6 
Cool tutorial! ;)
---
Pilou
Is beautiful that please without concept!
My Gallery
  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