Get your Helix here!

Fuccaro, would you mind posting the modifed helsurf script you used for the conical end?

The helsurf command works like a charm, but I can't make a conical ended screw.

Jose

I don't have it any more but I will rewrite it these days. Just I am *very* busy...

Hi fuccaro...

Where is the modifyed helsurf lisp routine for the conical end?

and about spirex routine, Did you already change the code to avoid the shape's flatness?

Do you Remember? you wrote:

Ok, probable the first modification will be the rotation of the shape perpendicular to the path to avoid the flatness.

*********************************************

Okay!! :wink:

Note:

Let's share and everyone will conquer.

ps: Continue the good work...

Hi,

I am new at using AutoCAD for 3D drawings, I'm used to Mechanical Desktop but at work they want me to use AutoCAD. To draw a screw I use (in Mechanical Desktop) a helix and a profile that is perpendicular to this helix and the command "sweep".

I found helix.lsp and I used it but I got a bad result because the profile that I extrude using the helix as a path doesn't seem to stay perpendicular to the path

So, does anyone know what am I doing wrong?

Ximena

First at all: welcome in the forum!

It is nothing wrong with you; just AutoCAD doesn't let you to controll the twist angle when you extrude along a 3D path.

My advice is: don't draw solid 3D threads. Use simple cilynders and in the 2D drawing add a thin line to show that it is a thread.

For 3D models: revolve the profile and array the resulted solid along the axis. You will get an... "almost thread" (no slope).

Or use surfaces.

It is possible to modell threads as solid, but it is time consuming and you will end up with huge files.

Thank you fuccaro, I have searched Internet and books trying to do a helix and a thread.

I guess I'll revolve the profile and use a "semi-thread". I noticed that if I use a circle as a profile I still have the slope and since it is symmetric there is no twist, so maybe I'll try this things to see what my boss prefers.

One more question, where can I learn about AutoLISP and how to write lisp programs for AutoCAD? I want to understand the logic that is used, they seem very useful, specially if one has to do one task over and over again.

Ximena

mmmkay... I know this is an old post and that I should take a little longer looking up for info but I realy can't get helsurf to work propperly.... I've drawn the line starting from (0,0,0) and ending in (0,0.05,0) to work as the rotation axis. I've drawn a triangle (as a test shape) with coordinates 1(0.026,0.0005,0) 2(0.0265,0,0) 3(0.026,-0.0005,0). When I try to helsurf it it spins on it's centre instead of creating a helix... what am I doing wrong? Thanks in advance for the help and sorry for botherring you folks. errr.. almost forgot.. I'm using ACAD 2006.

Very, very, very interesting...I made similar things in the past years and have included this works inside my "ARKLisp TNT" package, but what I'm wondering now is that AutoCAD 2007 seems to have finalyy solved this kind of problems...and all our works will be putted into the trash...or maybe not!?

ARKLisp

i have tried to create a parking ramp

but it's not that much accurate.

i have given outer radios 4.7m and inner radius .9m

i used helix for creating this

at first i created a circle centre of the ramp then given helix radius 2.7m bottom and 2.7m top

& given 2 turn for the height of 8.4m

but when i go to plan view it's not accurate

anyway i used sweep command for creating it's slab

friends somebody suggest the correct method for doing this here i attach my dwg file

How to create parking ramp.dwg

I am sure glad I found this site. Just the topic I am having problems wrapping my head around.

BTW..... Hi everyone.. I'm new to the forum.

When it comes to AutoCad 3D modeling I am a complete newbie. I am currently working on a project where I need to cut a helical slot in a cylinder which will become a cam. The cylinder will be stationary but there are other parts that will rotate inside the cylinder that will have cam followers on them that will follow the cam slot cut in the cylinder. Now it has been suggested to me to create the slot in the cylinder that I have already create the model for that I will need to create a helix and extrude along the helix path. Then subtract the helix model from the cylinder model. I am just not sure how to do this and could use alittle input.

Also I am having abit of trouble getting the codes for Helsurf and Helcon shown in this topic to work. I have copy'n pasted them into Notepad and saved them as .lsp, but when I load them into Autocad and try to run them I keep getting "Unknow command" error. I am not positive but I think it might have something to do with the ( at the beginning of each code line. Is this suppose to be a " ( " instead?

This is a image of the part I need to draw. Just not sure how to draw the slot.

It's hard to see but the slot has 2 straight sections. One at the top and one at the bottom.

Thanks

Hi Beezer, and Welcome to CADTutor

Since this thread is 9 years old, the code has gotten a little corrupted following server changes etc. so you will need to perform a find and replace:

Replace    With
(        (
)        )

Lee

Thanks Lee. I had a feeling it was that, since I compared the codes that didn't work with the ones that did and that seemed to be what was different.