I can't figure out why I can't trim the outer edge of the shape in the file.
You can see that projection works fine, but trim, by any of the methods I know(yes I've tried rebuilding the curve), does not work?

thx

Hi Ambimind,

The problem is your curve is not closed.
If you zoom up to the red cicled area in the picture you can see that the ends don't meet, also if you pick a curve or any object in MoI it tells you in the top right hand corner (circled green) what type of curve or object it is, in this case it says 'Curve' which means it's an open curve if it was a closed curve it would say 'Closed crv' if you fix this up so it's a closed curve it will trim as normal and no need for projection.





Cheers

Hi Ambimind - the problem is that the curve is not closed, if it was a closed curve, the object type indicator in the upper-right corner would say "Closed crv" when it was selected, but instead it says this:



So saying just plain "curve" there as the object type means it is an open curve - in order for trim to work the curve needs to be closed so that it fully divides the surface into different regions.

If you extrude it you can more easily see the open area:






EDIT: AAhh, Danny beat me to it! :)


- Michael

You got to be quicker than that Michael, must be the OSX stuff, that stuff can fry your brain ;)

-

And attached here is an edited version which should trim ok now.

I edited the curve by turning on control points and using the Transform > Move command to move the endpoints together and then deleted the ending point to make it a smooth juncture there.

You should now be able to use it as a cutting curve directly with Trim like Danny says you don't need to do a separate project step.

- Michael

> You got to be quicker than that Michael, must be the
> OSX stuff, that stuff can fry your brain ;)

iKnow

;)

Thanks so much guys, lesson learned in regard to curve type info.

I have to mention that I'm very relieved I'm at fault; I can't express enough the lethargy with which I considered going back to Rhino or SpaceClaim for this sort of work(scientific illustration)! A lethargy borne from knowing all the extra steps: the extra searching for, consideration between and use of their tools.

Moreover, I can't wait for the final release of v3, bending a Sine() around a circle is a pain. Although it was fun figuring out how to draw an accurate Sine():


Thx again,
Ambimind

Hi Ambimind, re: Sine - there is a plug-in you can get here for creating a sine wave curve, it may be useful:

http://moi3d.com/forum/display.php?webtag=MOI&msg=1519.38

- Michael

Hi Ambimind.

In the first step, how did you get the curve?
(Is your "sine" really a sine, or a parabola?)

(Michaels sine script works well, even for cosines...)

Hi Michael.
I noticed that the sinewave script uses the curve factory, and that the amplitude
shows up as a little shy of the selected amplitude. Gets better with higher number of points.

Tried script with change to interpcurve factory. The amplitude is closer to the selected amplitude, but zooming
way way in still shows a little off. (but within some tolerance?)

Not a big deal, unless someone is trying for a certain amplitude...?

Hi Brian, yeah the sine wave script just plots a lot of points for the control polygon hull and with more points the curve will approach the hull but not quite go exactly through it. It will be quite close though.

Using an interpolated curve will make the curve go exactly through the sampled points, I guess the script could be modified to make sure that there was a point being generated at the 90 and 270 degree spots.

But doing an interpolated curve is not necessarily automatically better - it kind of applies more force to the curve and can introduce a tiny bit of wiggling to the curve's shape. Using the control polygon hull will instead be super smooth with absolutely no wiggling of any kind.

- Michael

Thank you for the clarification.

bemfarmer, I used a "through points" curve. Its probably not exactly a plot of the sine() function. I used it because it easier to place and achieve an even curvature(what what I had in mind when I said "accurate").

Michael: The way you repaired the problem(join then delete the point) is completely new to me. Until now I have been rebuilding curves or scaling points so they are co-linear <- how dopy!!
Its interesting how habits and assumptions from other software persist.

Thx as always,
Ambimind