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Modeling
About Archicad's design tools, element connections, modeling concepts, etc.

Semicircular Mesh

Anonymous
Not applicable
Hello,
I have run into something strange with the mesh tool.
The attached image shows a semicircle drawn with arcs and lines.
Above that is a mesh made by tracing the figure made with arcs and lines.
When I go to the 3D window to view the mesh I get a warning
saying "Invalid polygon, self-intersection or hole intersects boundary".
Nothing appears in the 3D window.
If I trace the same figure using the slab tool or the roof tool and
go to the 3D window I get no warning and the slab or roof
show in 3D.
If I make an object out of the mesh using save selection as GDL Object
and open the objects 3D script and check script I get an OK but
if I go to the 3D view I get an error message saying
"Invalid curve definition at line......" and the 3D image fails to process.
I have tried this in both AC 8.1 and AC 9.
Would someone verify this behavior and perhaps
suggest a way to make such a mesh shape work.
I know that if I make the included angle one degree less than 180°
or make the inner radius 1/64" less than 10'-0" the error does not occur.
This work around is not satisfactory.
Thank you,
Peter Devlin
25 REPLIES 25
Anonymous
Not applicable
Hello Peter,

I'm not sure what could be causing this, I just created the mesh in the same way that you described, but I can't reproduce the error. Maybe it has to do with the magic wand tool, I have run into the same error when creating meshes with the magic wand tool... How exactly are you using it to create the mesh?

cheers,
dan
Anonymous
Not applicable
Daniel wrote:
Hello Peter,
... I have run into the same error when creating meshes with the magic wand tool...?
Hi all,

Daniel I have created semi- how Peter has described with magic wand tool and no error! How you poeple use wagic wand tool? I have done test on 3 main places of semi- using MWT:
1. inside (in different places)
2. along perimeter on different points
3. on corners
and no error!

So guys "How exactly are you using it?"
Anonymous
Not applicable
Hello Dan,
I did not use the magic wand tool.
I used pet palette tools exclusively.
You cannot reproduce this error?
I have drawn this shape maybe six or seven times and always
get the error when the dimensions are as I described.
I draw the arcs and lines as shown, then draw a four cornered
polygon with the mesh tool with one of it's edges laying across
and spanning the diameter of the larger arc and the remainder
of the mesh lies below this line.
Using the arc pet palette method I stretch this edge up to the
outer arc, then I drag the two remaining nodes to the left and right
ends of the inner arc, respectively.
Now I have half circle shape with four nodes laying in a line at the
diameter. Then, using the arc pet palette method I stretch
the edge between the two inner diameter nodes up to the inner arc.
I hope this is clear.
Thank you,
Peter Devlin
Anonymous
Not applicable
I actually drew two circles, one 1000mm dia, one 700mm dia, then I drew a line through the center point, and trimmed the line, and two cricles to the shape you are using, then I selected the mesh tool and click on the outside arc, and it worked fine...the only time I've ever gotten the error was when I imported a line drawing from AutoCAD and used the magic wand tool to create mesh points for a topographic site plan, and looking back on it, it was caused by intersecting mesh lines at different elevations.

hope this information helps

cheers,
Dan

EDIT: PS: What font is that that you're using Peter... off topic for sure, but I really like it
Anonymous
Not applicable
Hello Dan,
The font is called "MrHand".
I don't know if it is available for Windows.
It may be only for the Mac.
Thanks,
Peter Devlin
Anonymous
Not applicable
This is getting stranger by the minute.
I tried the magic wand tool on the arcs and lines
and it made a mesh that had the same error.
I then dragged a copy of both the flawed mesh I had
drawn and also the flawed mesh that was made
with the magic wand tool and both copies displayed
in 3D with no errors.
I don't understand.
Peter Devlin
Anonymous
Not applicable
riiiight... I'm not sue if thats another puzzle piece or if the ArchiCAD gods just snatched a piece out of your hand... I honestly have no idea what could be causing that.

cheers
dan
Anonymous
Not applicable
I got error(with MWT too),
formerly I have drawn with custom dims.

I don't know what's the problem is, but after short test have discovered that you/we have problem with inner Radius(not yet outer). And the problematic radius is in RANGE [9'-10" ; 10'-1"] (or in meters: RANGE [3.0000 ; 3.0700]).
Anonymous
Not applicable
Hello Z.Bauer,
In my test of the magic wand tool I just clicked
inside of the closed shape I had drawn with arcs and lines.
I was surprised to see that it made a tracing with two arcs
and two straight edges and four nodes rather than a polygon
with many nodes and straight segments.
I will have to check the magic wand settings.
Thanks,
Peter Devlin