Autodesk Inventor

[#1]

Gentlemen

  Can someone please point me to a detailed and complete description of the improvements in the 2013 release, OR

perhaps someone could check/verify that one specific isse has in fact been fixed.

The issue is the conversion of true arcs and circles on a drawing view into splines when the drawing is saved-as an Autocad DWG.

A quick test would be is to draw a 2" diameter cylinder, and drill a 1" hole through it's side.

When the drawining view is created with the hole normal to the viewplane, and the drawing is saved-as and AutoCAD DWG, the result of the hole will be ( on 2012 and previous releases ) a continuous spline instead of a true circle.

I have raised this very same question 3 times before, and the last time I was told it will be fixed in rel 2013.

I have the new release in the box, ready to install, but I truly don't want to rush it unless this spline thing is in fact fixed.

I would really appreciate it if someone could check it out and reply back with either a yay or nay.

Thank You

[#2]

Short answer...no it has not.  I tried both with AutoCAD Mapping and Visual Fidelity and I got the CV Splines both times.

Now after I bring it into AutoCAD, I can convert it to circles in a round about way, but if I was doing this all the time it would probably mean I would make a macro to do it for me, especially if I had a lot of these types of holes.

[#3]

Geez Mark, Thank You!

Must say I'm quite disappointed but there ain't much I can do about it.

If you don't mind me asking, what is the roundabout way?

I've tried just about every tool I know of in ACAD to no avail.

As it is, I always run Overkill to stich the connecting/collinear entities together, and that tool is awsome.

Unfortunately it does absolutely nothing for splines.

Neither does splineedit.

My way - truly roundabout - is to identify all splines, draw a matching circle on a different layer, turn off the layer, delete splines, turn on the layer, trim circles, curse for a while.

Gets exponentially more cumbersome with increased number of splines....

Am I really asking for something difficult to fix in Inventor? Is it really unreasonable?

[#4]

I change the PLINECONVERTMODE from 0 to 1

This creates arcs rather than linear segments.  Then I convert it with SPLINEDIT to linear arc segments.  That gives me the abiltiy to snap to the center and then the nearest with a new center point circle.  Then, yes I do delete the previous spline.

You could write this with a macro to speed it up a little.  You would have an object selection of the spline and then the conversion, the new circle, and then the erase of the selection set (might have to be a temporary group to work in coding).  At least that way the command is executed with little or no typing or input from you and it stops you from having to change layers all the time.

[#5]

I do a save as to R12 dxf, open the new file, save back to company standard ACAD format (2000  here). The translation turns any splines into arcs & lines.

[#6]

Hmm....

Is that a 2013 feature?

Just tried it on 2012 and it became a 3D polyline.

[#7]

Oops, forgot a step. It does work in 2012 (and should work in any edition).

1) Save as R12 dxf

2) Open dxf - splines are now plines

3) Explode plines - plines are now lines

4) Save as regular dwg format

[#8]

I must have something set incorrectly.

I do end up with lines after the explode, but that is what they will stay as even after the DWG save.

[#9]

That's the point...

Maybe I don't understand what you're trying to accomplish.

The geometery that is the result of the scenario you described above is not true arcs or circles, they are irregular. The way CAD software handles irregular arcs is with splines.

The method I described is what I use to convert flat pattern blanks of complex spline shapes to simple polygonal shapes for our CNC software to be able to read.

What are you trying to do that you need arcs for?

[#10]

Oh, I got where you've missed my point.

Take the example above, a cylinder with a hole through it's side.

The hole is not an irregular shape when viewed from a plane prependicular to the axis of the hole.

It is in fact a true circle, yet Inventor makes it a spline.

And since you've brought up the CNC software, that is one perfect example why this is bad.

The above mentioned spline is in fact a circle, which normally is recognized as a drilled feature.

If however it is represented as a spline, I do not know of any software that would recognize it as a drilled hole.

In case of mills/lathes, the result would be a boatload of code for the individual line segments to be profiled.

In case of a punch/laser combo, the hole would be laser cut instead of simply punched.

And that is just the CNC part of the problem.

If you want to use the DWG for detailng purposes, you'd never get anything usable to dimension to the hole or radius, even tough that's exactly what they are.