Beginner CAD - Creating Tangents

[Anonymous]

Hello Board!

Thanks for reading my first post! I'm looking for some help with CAD.

I need to find a CAD program that will do a couple of specific things. I am a product designer, mostly clothes or bags or purses etc.

The product flow i work with has some 'proper' CAD people who use Inventor or AutoCAD on PC to draw specific patterns and then manufacturing jigs and templates.

Instead of handing them a picture (an Illustrator drawing from a MAC) of a design and spending a lot of time working with them, i'd like to present a drawing and then a couple of the patterns - in CAD.

Now, I basically need to make two circles and then create a tangent line between them.

I have installed two CAD plugins for Illustrator, bought a copy of TurboCAD and now i'm looking for some information before i purchase another piece of software.

The tangent line needs to be the shortest possible distance between the two circles.

The problem i've come up against is that i can create a tangent line starting from the first circle, but then it is up to me and my mouse skills to lock the tangent onto the second circle. I can't do it mathematically perfect.

In AutoCAD, two circles are selected and then you click 'tangent line' and it puts the line inbetween the two.

I cannot afford AutoCAD or Inventor. I phoned a reseller and was told AC is now sold in a suite, like AdobeCS, which is £5K..... I just can't afford it and it seems like a huge waste. I wouldn't use 1% of Inventor.....

Can ArchiCAD do what i want?

Is there a better alternative for the Mac OS? I run windows also on my Mac, is there an option that will export to DXF or DWG and do what i need?

Thanks for any input you can give me, a complete CAD novice.

HB@

[Dwight]

High Design $99. 12 hour tryout period

Download

[Karl Ottenstein]

If you've looked into ArchiCAD at all, you'll know that it is designed for Architecture, not creating free form products such as "clothes or bags or purses etc.". It is also very expensive - and your comment on AutoCAD suggests that you're looking for something cheap.

The cheapest thing is free: SketchUp. If you need to export to dwg, then you need to purchase the 'Pro' version, which is still one of the cheapest Mac options out there. A tutorial (as a Sketchup file - click through the 'scenes' to see the steps) that shows how to create a tangent between two circles is here:
http://sketchup.google.com/3dwarehouse/details?mid=13c5c00fdd7b0cb4578ab59bb235330e

That geometric construction method will work in any CAD software. It is not automatic such as what you mentioned exists in AutoCAD.

Other Mac CAD software includes TurboCAD (cheap) and, Vectorworks.

[Karl Ottenstein]

Dwight wrote:
High Design $99. 12 hour tryout period

Interesting!

[Dwight]

A drafting-like interface, a one-step tangent function as the poster requested and DXF output!

[Anonymous]

For Mac there is DraftSight, a FREE AutoCAD (v2008) clone from Dassault Systemes.

http://architosh.com/2010/09/dassault-systemes-releases-draftsight-2d-cad-system-for-mac/

[Eduardo Rolon]

+1 on Draftsight.

[Dwight]

How can any of these CAD companies make any money?

[rocorona]

The "shortest" line between two circles is not a tangent.
The tangent is the longest line that touches the circles without crossing the circumferences.
For the shortest you simply join the circle centers then delete the inner parts on the line (seems obvious, but can be the searched function)

[Eduardo Rolon]

Dwight wrote:
How can any of these CAD companies make any money?

One urban legend is that Autodesk (Inventor) got on the wrong side of a fight with Dassault Systemes (Solidworks) and they decided to kill Autocad.

The other is that DS was loosing customers because they were afraid to stop upgrading their Autocad to avoid losing compatibility and because of this they only could afford one software package.

That was the reason that they created a Plug-In for all Autocad releases that was able to save-as to R-12 and to open the most recent version regardless of which release of Autocad you had installed and this is the next step.