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Spline, Detailed explanation on How to draw.

jimbir
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Spline, Detailed explanation on How to draw.

jimbir
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Hi. I've been using auto CAD version 2004 (I think it's the Cro-Magon editions since it came out. I continue using it because I can't afford any of the newer editions and it does all that I need. Yesterday I got involved in trying to draw a wingtip of a P 39 aircraft. Since it's neither circular or oval shaped, I tried using the spline drawing tool. I have three known points and am able to draw a spline between them. When I come to the third point and am ready to apply the spline, I'm lost with all the selections I'm presented, close/fit tolerance, start, tangent. The spline looks to be the correct shape but, it is not tangent to the end of the line which represents the leading edge of the wing. The final problem is, I can't finish/apply the spline to the drawing because I just don't know how to do it. Can anybody explain the step-by-step details of how to finish drawing the spline and explain how to use the selections I mentioned above or lead me to a complete tutorial on how to do this?

Thanks. Jim

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leeminardi
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@Alfred.NESWADBA  do you know how to display a spline's control vertex polygon in AutoCAD 2004?

Thank you,

 

Lee

lee.minardi
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Alfred.NESWADBA
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Hi,

 

>> do you know how to display a spline's control vertex polygon

Are you looking for system variable SPLFRAME (>>>details<<<)? Works the same way in 2004.

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2025
------------------------------------------------------------------------------------

(not an Autodesk consultant)

jimbir
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Maybe I should upgrade. Do you know what the last standalone release of auto CAD was??

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leeminardi
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Thank you @Alfred.NESWADBA.

I tried setting splframe to 1 in AutoCAD 2019 and as the documentation you reference implies, it does not show the CV polygon for splines, only helixes and mesh objects.  CVSHOW will show the CV polygon but I could not edit the CVs. To do that I need to use splinedit  or change the method property to Control Vertices.

 

I am trying to help the OP who is using 2004 and don't know if splinedit was in that version. Do you know or can you point me to where I could look?  I would like to know how to modify the location of CVs in 2004.

 

Thank you,

 

Lee 

 

 

lee.minardi
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Alfred.NESWADBA
Consultant
Consultant

Hi,

 

that is what you see in 2004 when SPLFRAME is set to 0 and you have selected the spline

20191025_221524_0001.png

 

that is same with SPLFRAME set to 1

20191025_221604_0001.png

 

Sorry that I have not read the whole thread, just reacted to your last question.

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2025
------------------------------------------------------------------------------------

(not an Autodesk consultant)

leeminardi
Mentor
Mentor

@Alfred.NESWADBA Can the CVs then be selected in 2004 and be moved independently of each other?

 

In 2019 splframe will show the CV polygon (for exaple, a helix) but you cannot select the CVs.  YOu need to change the method to Control Vertices or use splinedit.

 

@jimbir is there a splinedit command in 2004? 

 

lee.minardi
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Alfred.NESWADBA
Consultant
Consultant

Hi,

 

>> Can the CVs then be selected in 2004 and be moved

>> independently of each other?

Yes, please find the video, sorry that I only have a German version of AutoCAD 2004 (Land Desktop).

 

>> is there a splinedit command in 2004?

Yes

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2025
------------------------------------------------------------------------------------

(not an Autodesk consultant)
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leeminardi
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Solución aceptada

@Alfred.NESWADBA thank you.

 

@jimbir  OK, here's how to make the spline tangent to the lines.

  1. Create a spline from #1, to #2 to #3.
    image.png
  2. Display the Control polygon.  In 2004 use splframe and set it to 1.  It may display differently in 2004 (this image is from 2019) but you should see 5 CV points. There will be one at each end.
    image.png
  3. Use osnap nearest and move the 2nd and 4th CV so that they are on a line that is an extension of your original lines.  The further the 2nd CV is from the end of the line the larger the radius of curvature at #1.
    image.png
lee.minardi
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jimbir
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Good morning Alfred. I'm the guy using auto CAD 2004 who started this thread. Lee Minardi has been very patiently putting up with me trying to help me with my spline problem. Thank you for putting me onto SPLFRAME. I've been experimenting with it and it does everything I want.The one problem I'm having with it is, I can't figure out a simple way To remove it when I'm finished using it. The only way I am able to do it now is to type SPLFRAME, set it to 0, then click on it and erase it. The spline is also erased at the same time. If I undo the erase command, the spline comes back without the frame. Do you know a more efficient way to remove the spline frame?

 

Jim Birke

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Alfred.NESWADBA
Consultant
Consultant

Hi,

 

>> The one problem I'm having with it is, I can't figure out a

>> simple way To remove it when I'm finished using it.

Press <ESC> after your modifications, so the grips should disappear (as well as the dahsed connections between the control points). If they do not disappear then you have an issue with your graphic card, try to run command _REGEN after you used <ESC> ... does that help?

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2025
------------------------------------------------------------------------------------

(not an Autodesk consultant)

jimbir
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Thank you for this, it solves the problem. I contacted Alfred to see if he could solve the only problem I'm having with it. Thank you so much for being patient with me during this episode. I can now get back to being productive. I take it you have a ton of experience using auto CAD. When my next problem comes up, I'd like to be able to contact you or Alfred directly. Is there a way to do that on this forum? Thanks again. You get five thumbs up from me.

Jim Birke

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Alfred.NESWADBA
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Consultant

Hi,

 

>> I'd like to be able to contact you or Alfred directly.

>> Is there a way to do that on this forum?

In general yes, there exists a private message option here, but ... (speaking just for me) ...

  • I'm active in forum to learn and to help others to learn. This only can happen when questions and answers are public, not within the private messages.
  • Asking in public means you get a lot more people reading your question and reacting on that ... so you get more ideas for how to solve your question ... and you don't need to wait until one specific person has time to read PM
  • I'm working here for free (and I love to help here) ... having multiple users sending me support tickets via PM and I have to solve that (for free) means my boss gets angry and my child hungry...

Please understand that asking in the forum makes much more sense, for you as well as for others, that's what community stands for!

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2025
------------------------------------------------------------------------------------

(not an Autodesk consultant)

jimbir
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I understand fully.

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jimbir
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Thanks for the reply and help.
The ESC command worked but I had to set SPLFRAME back to 0 before the REGEN command would work.

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leeminardi
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@jimbir ,  I agree with @Alfred.NESWADBA It is best to keep your questions public.  

 

I am glad you finally got the answer to your question.

 

Lee

lee.minardi
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jimbir
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"It is best to keep your questions public."

 

I will...

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