AnsweredAssumed Answered

Loft profile with hole

Question asked by Igor Rybalka on Jul 2, 2013
Latest reply on Jul 4, 2013 by Igor Rybalka

Like • Show 0 Likes0
Comment • 5

Hello everyone,

I'm sorry if this was already answered, I didn't find such topic on forum.

My problem is that I want to make a loft for a profile that have a hole.

I cannot use loft cut after a loft because I do not have a guide curves for inner hole profile. I do not even know what shape this hole actually should become after a loft.

My two guide curves are complicated and they are adjacent only to outer profiles and if I try to use them for inner hole profile - SW goes crazy and twists inner cut loft in a very strange way. My guess that this is because they are too far away and actually not applicable for it. What should I do?

Thank you for any suggestions.

Igor.

Kieran Choy Jul 2, 2013 11:06 PM

Correct Answer

I lied. Here's an attempt with a deformed hole. It's possible, but not necessarily pretty or "correct". If you understand the general method below you can try tweaking how the guide curves are made to maybe get a better result.

Basically I'm using lofted surfaces as a way to create edges that are curves that are the "average" between two existing curves. So the ruled surfaces allow me to create an intersection curve along the outside edge of the part, and then we can use our loft surface to create an edge that theoretically is the ratio between the circle center and circle edge, to the circle edge and the outside of the part.

Hope this makes sense. I still if it's possible a sweep would be a better option.

See the reply in context

No one else had this question

Outcomes

Anna Wood Jul 2, 2013 12:27 PM

Post your part with what you have tried. Use the Advanced Editor link in the upper right of the dialog box.

Cheers,

Anna

Actions

Igor Rybalka @ Anna Wood on Jul 2, 2013 4:20 PM

Hello Anna,

Please see part attached. What I am basically trying to achieve - is to have a inner loft cut that will follow the shape of the outer loft base.

Thank you.

Igor.

Attachments

LoftWithHole.SLDPRT.zip219.5 KB

Actions

Kieran Choy @ Igor Rybalka on Jul 2, 2013 10:43 PM

I'm not sure if this is possible with the geometry you've supplied. The reason you can't loft the two circles together with the existing guide curves is because guide curves must pierce (touch) the sections. Centerlines (like sweep paths) do not have constraint, but you can only use one curve at a time.

I've attached my attempt, which is a potential start.

The Surface loft is used to create an edge, which can then be selected as a centerline (or guide curve) for the Loft cut.

The problem, as you can see, is that because the two profiles are circles, the cross section remains circular throughout the loft, and end up cutting through the original body. This is because the original body has two elliptical ends but does not have an elliptical cross section throughout. So you would need to try and work out what shape the circles would become as the outside profiles are deformed, which as far as I know is impossible to do in SW.

If this was a sweep and your geometry was slightly different this would be much more easy to solve - is this possible?

Attachments

LoftWithHole_KC.SLDPRT.zip178.0 KB

Actions

Kieran Choy @ Kieran Choy on Jul 2, 2013 11:06 PM

Hope this makes sense. I still if it's possible a sweep would be a better option.

Attachments

LoftWithHole_KC_2.SLDPRT.zip279.3 KB

Actions

Igor Rybalka @ Kieran Choy on Jul 4, 2013 4:03 AM

Hello Kieran,

Unfortunately I cannot use sweep as the real part is a wing and airfoil does change its shape along the way. Nor hole is a simple circle - it's a bit more complicated. But I've got the main idea - use lofted surfaces to approximate curves for some "key" points that can be used later as reference when lofting a hole.

You are right that I have know what shape the hole would become to make the loft "correct", but approximation based on distance to the edges is good enough in my case.

Thank you!

Actions

5 Replies

Anna Wood Jul 2, 2013 12:27 PM
Mark Correct
Correct Answer
Post your part with what you have tried. Use the Advanced Editor link in the upper right of the dialog box.

Cheers,

Anna
Like • Show 0 Likes0
Actions
- Igor Rybalka @ Anna Wood on Jul 2, 2013 4:20 PM
  Mark Correct
  Correct Answer
  Hello Anna,
  Please see part attached. What I am basically trying to achieve - is to have a inner loft cut that will follow the shape of the outer loft base.
  
  Thank you.
  Igor.
  Attachments
  - LoftWithHole.SLDPRT.zip219.5 KB
  Like • Show 0 Likes0
  Actions
  - Kieran Choy @ Igor Rybalka on Jul 2, 2013 10:43 PM
    Mark Correct
    Correct Answer
    I'm not sure if this is possible with the geometry you've supplied. The reason you can't loft the two circles together with the existing guide curves is because guide curves must pierce (touch) the sections. Centerlines (like sweep paths) do not have constraint, but you can only use one curve at a time.
    
    I've attached my attempt, which is a potential start.
    
    The Surface loft is used to create an edge, which can then be selected as a centerline (or guide curve) for the Loft cut.
    
    The problem, as you can see, is that because the two profiles are circles, the cross section remains circular throughout the loft, and end up cutting through the original body. This is because the original body has two elliptical ends but does not have an elliptical cross section throughout. So you would need to try and work out what shape the circles would become as the outside profiles are deformed, which as far as I know is impossible to do in SW.
    
    If this was a sweep and your geometry was slightly different this would be much more easy to solve - is this possible?
    Attachments
    LoftWithHole_KC.SLDPRT.zip178.0 KB
    Like • Show 0 Likes0
    Actions
    - Kieran Choy @ Kieran Choy on Jul 2, 2013 11:06 PM
      Unmark Correct
      Correct Answer
      I lied. Here's an attempt with a deformed hole. It's possible, but not necessarily pretty or "correct". If you understand the general method below you can try tweaking how the guide curves are made to maybe get a better result.
      
      Basically I'm using lofted surfaces as a way to create edges that are curves that are the "average" between two existing curves. So the ruled surfaces allow me to create an intersection curve along the outside edge of the part, and then we can use our loft surface to create an edge that theoretically is the ratio between the circle center and circle edge, to the circle edge and the outside of the part.
      
      Hope this makes sense. I still if it's possible a sweep would be a better option.
      Attachments
      LoftWithHole_KC_2.SLDPRT.zip279.3 KB
      Like • Show 0 Likes0
      Actions
      - Igor Rybalka @ Kieran Choy on Jul 4, 2013 4:03 AM
        Mark Correct
        Correct Answer
        Hello Kieran,
        Unfortunately I cannot use sweep as the real part is a wing and airfoil does change its shape along the way. Nor hole is a simple circle - it's a bit more complicated. But I've got the main idea - use lofted surfaces to approximate curves for some "key" points that can be used later as reference when lofting a hole.
        You are right that I have know what shape the hole would become to make the loft "correct", but approximation based on distance to the edges is good enough in my case.
        Thank you!
        Like • Show 0 Likes0
        Actions

Loft profile with hole

Outcomes

Attachments

Attachments

Attachments

Related Content

Recommended Content