closed shapes

[hansgeerdink]

Hi,

Again I am having trouble creating closed surfaces using the extrude tool.
Please check the accompanying pictures....

Ok I have:
- created single curves and lines, connected them and extruded them.
- created single curves and lines, then aligned them tangential using the new align tool, and extruded them.
- created single curves and lines, then aligned (as above), connected them, closed them using the close tool, and extruded the resulting curve.
I always check the direction of the curves to make sure ends meet starting...

Any how I try to create the surfaces I always end up with the red arrows indicating the surface is not closed. (I believe...)

Same counts for the front and back caps if created, they somehow do not match to a degree a good shell can be created from them. (either caps or a single trimmed surface, created by the planar tool) Again I always check the directions from the normals to make sure all are pointing outwards...

My goal is to create a guitar-neck shell and subtract it from a guitar-body shell in order to create a pocket in which the guitar-neck fits perfectly. This is doable, however I must always fool around with the precision (in the Construction Options) or mess with all possible ways to create the initial geometry, because after the pocket is created I must round all edges, varying from say 2,0 mm to 12,5 mm ... and things get really messed up if all is not geometrically correct..

So, my question would be:

How does one create a shape out of multiple curves, lines, etc. making sure the result is closed (and/or to what degree)... At least close enough to stitch to a good shell being able to do the boolean subtract thing without problems (message: there are gaps on both shells so no way Jose)

Oh yeah, grabbing the chance to whish all here a very happy new year!!!!

Cheers!

Hans

[hansgeerdink]

I will not start complaining about the messageboard software...
Here is the second picture

[aberendt]

Hello Hans,

I am trying to duplicate your problem. Unfortunately I am not experiencing the issues you are describing,
Would you be willing to send me the .wire file you are working on so I can see what is going on?

Regards,
Aaron Berendt
INCAT
Alias Applications Engineer

aberendt@incat.com

[hansgeerdink]

Hi Aaron

Thanks for relying!
Did not want to send the file, might be I have errors in my blends... however I have simplified my words in a wire file.

I created a real simple example using lines and blend curves.
First I created the blends and assigned G2 continuity from endpoint line one to startpoint line two, assuming I was creating poerfectly alined and connected geometry....

Layer CurvesAndLines
- separate lines and blendcurves (G2), same direction.
Extruded along line at 0 0 0.
Layer singleCurve
- connected lines and blendcurves. Extruded along line at 0 0 0.
Layer closedCurve
- connected singleCurve to itselve (hoping to close the shape). Extruded along line at 0 0 0.

Why do I still have major problems trying to get a clean closed shape so I can transfer them into stitched shells and do boolean operations on them?

Have I missed something while creating the blendcurves between the lines?

Cheers!
Hans Edited by: hansgeerdink on Jan 8, 2009 9:37 PM

[hansgeerdink]

strange upload issue...
Again I won't start complaining about the blogsoftware.... pfff

This link should point to a copy of the wire file:
http://hansgeerdinx.hobby-site.com/jhgdesign/StratNeck_Issue_0.wire

There should also bee some more screen shots in there:
http://hansgeerdinx.hobby-site.com/jhgdesign/

Cheers!
Hans

[aberendt]

I opened your file and everything stitches up perfectly for me. I kept your constructions settings and used the default stitch settings. I don't see anything wrong in the model you sent me. If you modeled your guitar neck the same way you should be fine.

You may want to try adjusting the settings for the stitch tool. Uncheck the use construction setting box and manually give it a tolerance to use. Adjust the tolerance until you get a clean shell.

Another option would be to not use the Boolean tools and just do a intersect and trim on your neck and guitar body. Duplicate the neck surfaces so you have two copies. Intersect one of thoes copies with the guitar body and trim the surfaces to create the pocket. This would be the way I would create the pocket. I don't trust the stitch tool. It has the potential to alter the surfaces you are stitching and that is not something I want.

Hope this helps.

Regards,
Aaron

[hansgeerdink]

Hi Aaron,

OK, I understand that I somehow must be to be more specific (in order for me to understand....)
Please refer to the linked file and picture.

Anyway... You are right if you stitch the third layer (closedCurve) I also do get a nice shell (even manually set tolerance of approx. 0.001)

The question remaining would be Why?
picture: http://hansgeerdinx.hobby-site.com/jhgdesign/StratNeck_Issue_4.jpg

Why do I have to connect all lines and curves before stitching? (when aligning tangent, I assume there is already a constraint in history...)
picture: http://hansgeerdinx.hobby-site.com/jhgdesign/StratNeck_Issue_5.jpg

This brings me to my main problem, somehow when a curve is bending in two directions Alias Studio somehow does not Attach cleanly...(?)
picture: http://hansgeerdinx.hobby-site.com/jhgdesign/StratNeck_Issue_6.jpg

When trying to close the curve using the Object edit -> Close tool results in a message (see command line) : "Curve is now closed. Select another obect to close or open."
picture: http://hansgeerdinx.hobby-site.com/jhgdesign/StratNeck_Issue_7.jpg

However closer examination with the Object edit -> Queryedit reveals the FORM as PERIODIC (uh.... is this closed???) however still lots of red arrows warning me it does not make sense trying to extrude or bi-rail the curve....
picture: http://hansgeerdinx.hobby-site.com/jhgdesign/StratNeck_Issue_8.jpg

All applies to the following wire file:
file: http://hansgeerdinx.hobby-site.com/jhgdesign/StratNeck_Issue_1.wire

Now, to be honest yes, I can indeed create shells without red arrows.... Although I must fiddle with the tolerances...
So I created a body shell and neck shell making sure tolerances are the same on both shells, hoping to be able to subtract the neck shell from the body shell.
picture: http://hansgeerdinx.hobby-site.com/jhgdesign/StratNeck_Issue_09.jpg

Again no luck, the boolean operation complains and states there may be gaps on both shells and therefore it cannot compute a resulting volume..... As you can see in the next picture my shells are closed volumes, I can create a cut-out by using the union boolean operation between my body shell and a shell created from a standard cylinder...
picture: http://hansgeerdinx.hobby-site.com/jhgdesign/StratNeck_Issue_10.jpg

What also confuses me is the boolean operation subtract does not result in a cut-out, I had to do a union???
Thus I tried all possible booleans on the body and neck shells, trying to create my neck pocket, however none worked.....
file: http://hansgeerdinx.hobby-site.com/jhgdesign/StratBody&Neck_00.wire

All I would like to model is a nice neck-pocket like so : http://hansgeerdinx.hobby-site.com/jhgdesign/faq_neck_pocket.jpg
Hope you can still help me further on my modeling way...

Cheers!
Hans

[hansgeerdink]

Hi Aaron,

After some more foolin'round I came up with a solution...
Looks like my workflow was somewhat error prone, I had created a body shell following the guitar body contour and wanted to "cut"out the neck pocket.

Now when I (actually like I would in the real world....) start with a cube the same thickness of the final body, the width and length large enough to just overlap the contour. After creating a shell from the cube I can subtract the neck shell from the cube shell.
picture: http://hansgeerdinx.hobby-site.com/jhgdesign/Solution_1.jpg

My previous body shell can now be "boolean united" with the above created shell.
picture: http://hansgeerdinx.hobby-site.com/jhgdesign/Solution_2.jpg

Resulting in a perfect pocket for the neck.
picture: http://hansgeerdinx.hobby-site.com/jhgdesign/Solution_3.jpg

Finally I can continue rounding and contouring both body and neck, after saying thank you for your enlightening remarks!

Cheers!
Hans