helix on cylinder

[andymel]

How do I extrude a profile over a cylinder? i.e. I have created a closed polyline profile of a gear tooth and want to extrude it over a cylinder, but it must have a 16 degree helix angle. If it was straight it would be easy, I just don't know how to create a path over the cylinder that takes this curve. I've tried playing with the spiral lisp file thats been posted but have had no success. I could send you the profile if anybodys willing (Mr T - I'm begging - help).

[Mr T]

See my post in the topic below yours.

Nick

AKA Mr T

[andymel]

Thanks for the advice, I read the post but I'm not sure that this type of helix will work. From what I understand, you can extrude any type profile along this type of 3dpolyline. I'm trying to extrude a profile along a straight line while twsting the outside. I think the correct term is an involute spline, sort of taking a cylinder, holding one end fast and twisting the other. Hope this makes it clear - or am I just an idiot?

[Mr T]

If you drew a cylinder within my boxs/floors ie the width of the box is the diameter of a cylinder then that's what you are looking for. Done on here.

http://www.eezylearn.pwp.blueyonder.co.uk/images/spiral3.png

Change the sizes and frequency of the points I have snapped to to increase the smootheness etc. Or draw the spline using relative coords to go round an imaginary circles quadrants.

Nick

[Mr T]

Thanks for the advice, I read the post but I'm not sure that this type of helix will work. From what I understand, you can extrude any type profile along this type of 3dpolyline. I'm trying to extrude a profile along a straight line while twsting the outside. I think the correct term is an involute spline, sort of taking a cylinder, holding one end fast and twisting the other. Hope this makes it clear - or am I just an idiot?

PS have you downloaded the file and looked at it with '3DO' ?

Nick

[andymel]

Thanks, I see where you're going with this. One question - can you extrude a cylinder face by selecting this path? i.e. selecting one of the circles (or any profile for that matter) and choosing the spiral as a path. I thought this couldn't be done with a splined polyline, but I might be wrong.

I could only download the .png file - do you have a link to the .dwg?

Thanks Mr T - you are a machine!

[fuccaro]

andymel
Here is my work, but it is a surface, not a solid. I wrote a Lisp routine to extrude and twist a polyline. You may try it but not for free: it will cost you about 10 minutes from your life!
A possible solution: draw a tooth, create the surface and convert it to solid. A nice routine called m2sol it is free ower the Net, probable it will do the job. Than you need just to aply a polar array and a reunion to complete the solid.
I wil try to post an image of my surface here, but I have problems with my web host. So if the image is not here, please try this URL http://www.fuccaro.netfirms.com
Please tell me how you construct gear tooth profile?
http://www.cadimage.net/fuccaro/rd.gif

[andymel]

Thanks Fuccaro, thats really cool and exactly what I'm looking for.

I'm assuming the lisp file you mention was posted some time ago? I got hold of what I think was the extrude & twist lisp file yesterday - the command to run it is etw?

My problem all along has been trying to do this as a solid - again I didn't know you could convert from a surface to a solid so now I've been given new hope! I'll look for that lisp file immediately.

A good way to draw a gear tooth profile (apart from sitting with various design textbooks) is to use a lisp routine I've been using for some time called truegear.lsp. Its available on the net (in a zip file). If you can't find it, let me know, I'll try & get it to you.

Thanks Again

Andy

ps - much respect for the priza6.gif on your website - surely you didn't do that on autocad?

[fuccaro]

Thank you Andymel!
The extension cord with plug and 6 sockets (priza=socket) is modeled and rendered in AutoCAD2000.
I wrote long time ago a lisp routine for gear profiles (evolvent? sorry, my dictionary can not help me here) and I am curious about other solutions.

[andymel]

Thanks again Fuccaro, I got your lisp ETW working - and it works perfectly.

The bad news is that I cannot convert this surface to a solid (not properly).

Thanks to everybody for all their effort, but I now believe this solid cannot be correctly created in autocad. Solidworks here I come!

[fuccaro]

Well, we assist to the loose a poor soul...
Andymel PLEASE do not turn your face from AutoCAD. To convince you to stay with us, I will tell you a big secret: using the ETW.LSP routine, you may adjust the surface quality by setting the SURFTAB1 to a higher value. If you switch to Solidworks, let us know your impressions.
Cheers!

[Leby-Bautista]

If you drew a cylinder within my boxs/floors ie the width of the box is the diameter of a cylinder then that's what you are looking for. Done on here.

http://www.eezylearn.pwp.blueyonder.co.uk/images/spiral3.png

Change the sizes and frequency of the points I have snapped to to increase the smootheness etc. Or draw the spline using relative coords to go round an imaginary circles quadrants.

Nick
Hi Mr. T, I have been reading most of your help and I am impressed, you are the best, I have seen your drawing at your site but no instruction on how to get your lsp, can you please let me know on how to get it? I am an autocad student here in california and you drawings are some of my assignment,

Thanks

Leby Bautista

[Leby-Bautista]

andymel
Here is my work, but it is a surface, not a solid. I wrote a Lisp routine to extrude and twist a polyline. You may try it but not for free: it will cost you about 10 minutes from your life!
A possible solution: draw a tooth, create the surface and convert it to solid. A nice routine called m2sol it is free ower the Net, probable it will do the job. Than you need just to aply a polar array and a reunion to complete the solid.
I wil try to post an image of my surface here, but I have problems with my web host. So if the image is not here, please try this URL http://www.fuccaro.netfirms.com or this one:http://fuccaro.1hwy.com/
Please tell me how you construct gear tooth profile?
http://www.cadimage.net/fuccaro/rd.gif

Hi, I am an student of autocad here in california, could you please help me get the lisp to make this gear twisted, it is one of my assignment.

Thanks,

Leby Bautista

[fuccaro]

Hello Leby and welcome!
You will find the Lisp routine in this Forum; check the AutoLisp section, Free Lisp routines (or just follow this link http://www.cadtutor.net/forum/viewtopic.php?t=159).
I draw the half of the profile with free-hand and I mirrored it. It is just a quick sample image to prove the possibilities of the ETW (Extrude and Twist) routine.
Cheers

[Leby-Bautista]

Hello Leby and welcome!
You will find the Lisp routine in this Forum; check the AutoLisp section, Free Lisp routines (or just follow this link http://www.cadtutor.net/forum/viewtopic.php?t=159).
I draw the half of the profile with free-hand and I mirrored it. It is just a quick sample image to prove the possibilities of the ETW (Extrude and Twist) routine.
Cheers

Thank you so much for the time and effort exerted in helping me, rest assured that this will not be the last, I will be coming back for more information.


Again, thanks

Leby

[Punannilover]

Eariler in this post you talked about a routine called m2sol can you tell me where to find it? thank you much appreicate your help on here your awesome

[fuccaro]

My oppinion: this routine is ingenious and very useful. It is created to draw a prismatic solid with a profiled top. The profile is a surface constructed before start the routine
http://www.accustudio.com/marketplace/freeware.htm
The correct name is m2s

[Punannilover]

:D Thank you for your quick response. Im gonna go check it out. thanks again :D

[Punannilover]

Hi again, hope you can help some more I got that lisp and tried to apply it to a helix I made using your helsurf lisp it didnt work the way I thought it would Is there any way you know of to make a solid helix with a profile other than a circle?
Thanks for your help

[Mr T]

Thanks, I see where you're going with this. One question - can you extrude a cylinder face by selecting this path? i.e. selecting one of the circles (or any profile for that matter) and choosing the spiral as a path. I thought this couldn't be done with a splined polyline, but I might be wrong.

I could only download the .png file - do you have a link to the .dwg?

Thanks Mr T - you are a machine!

Yes, see my extrude tutorials. on www.autocadzone.com

I do not use lisps, just sensible construction and drafting in 2D first. I have to teach kids how to draw models only using modelling.

Any closed profile may be extruded along a path, as long as it doesn't intersect (overlap, collide) with itself. What you are wanting is easy with a surface. Any 'open' edge/line/profile can be pseudo extruded with TABSURF.

Nick

http://www.eezylearn.pwp.blueyonder.co.uk/images/spiral.dwg
http://www.eezylearn.pwp.blueyonder.co.uk/images/spiral2.dwg

[Mr T]

Also look at the 'spiral staircase' post to see how a profile has been extruded along a path.

Nick

[Punannilover]

Hi, When i try to extrude a profile other than a circle along a helix path the shape twist as it extrudes, Is there any way to keep this from happening
http://onester.kidulus.com/spiral.JPG (http://onester.kidulus.com/)

[Mr T]

[quote="Punannilover"]Hi, When i try to extrude a profile other than a circle along a helix path the shape twist as it extrudes, Is there any way to keep this from happening
quote]

It depends on the orientation of the profile before it extrudes and if it's paralell to the UCS etc.

Good luck

Nick

[Punannilover]

Hello Again, I constructed the face that you can see in the picture I posted last, Parell to the front ucs and the helix looking from the top ucs is a circle, how would I keep it from spinning? Like my Avatar? Thats the first time I tried to make my own texture and apply it. Thank you for your help

[Flores]

Thanks to everybody for all their effort, but I now believe this solid cannot be correctly created in autocad. Solidworks here I come!

Solidworks? I hear it's an awesome program, but I have yet to see something drawn in Solidworks that I haven't been able to produce in Mechanical Desktop 6. It's sad to see that Autodesk is pushing it out in favor of Inventor.

Flores

[andymel]

I think you're right - I've no doubt you can produce just about anything in autocad. To be honest, I wrote that comment in a fit of rage (just after having a quiet cry in the corner). I'm using Autocad 2000 and I'm sure its not designed for this type of work. Mechanical desktop would definetely be another answer.

I must say, however, that an engineer that does contract work for us showed me what can be done on solidworks. The problem I've been carrying on about was solved in about 30 seconds using standard lofting commands. I was dumbstruck - the word add-on (or lisp) did not even enter the conversation. He then proceded to draw the mating gear, produce an .avi file showing rotation and then generated a sheet giving me axial/tangential forces. In about 5 minutes. Damn, don't you just hate showoffs?

[Mr T]

It's like all software once you know the tricks then things look amazing and awsome. My school kids have discovered how cool and realisitc rendered images look when the lighting is atmospheric and subtle.

Nick