Newbie questions, transforming object, exporting single face of object

ZooHead

Well-known member
Here's a version I created to get a better look at the interaction of the forms.

schwung elements render.jpg
 

GS089

Member
That is cool and frightening at the same time.. ;) Yes I want to build it with 3mm hdf Wood, the whole sculpture will be around 3m in length. I think the curved element will be the biggest challenge.

When thinking about the laser cut.. is it possible to have the elements (with that uv-thing) named after the element in cheetah3d? There will be hundrets of small lookalike part with should be clearly identified. ;)

Thanks
Gerald
 

ZooHead

Well-known member
When thinking about the laser cut.. is it possible to have the elements (with that uv-thing) named after the element in cheetah3d? There will be hundrets of small lookalike part with should be clearly identified. ;)

Thanks
Gerald
I have given that some thought, but I need more information about your
process and laser cutting in general to figure the best procedure.

How do you deal with the relative scale of the parts?
If I uv unwrap one part at a time the scale will be different.
Do you adjust scale in Illustrator or another program?
Does the laser cutter do beveled edges?
Do you name the "elements"?
 

GS089

Member
Thanks, I will send you my projects file with more information. That scale thing I does not understand, every element in my 3d model has its fixed size, right? How does unwraping change that? Ok that curved element change there size when placing on a flat surface, I hope. 3mm hdf is quite thin and I hope I can bend it to fit the curves...
Beveled edges would be nice, but for now I really dont know, i my other sculpture is use another joining method (see attachemnt) it's easy to build, I will do draw the cuts in illustrator, but of course you can see this joining method later under the painting, even with filling and sanding.

Bildschirmfoto 2022-05-16 um 15.33.49.png
 

GS089

Member
But looking at that curvy element, that is too curvy for 3mm hdf, maybe 0,8mm of wetted plywood will work...
 
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ZooHead

Well-known member
The uv's are used for applying materials and graphics to a 3d model and they
are not related to the size of the model. Uv's are essentially dimensionless.
If I scale a model up or down, the same uv map will work.

In Cheetah when you uwrap something, it fills the uv window, regardless of the size of the object.
The uv window represents a final pdf size of 2133 pixels I believe, at least in Photoshop.
 

ZooHead

Well-known member
In terms of labeling the elements, I can open the pdf in PS and label each item and color them as well.
Then save as a jpeg, load into Cheetah as a material. Maybe this could be a good visual reference guide.
This uv jpeg can also be printed out of course.

Cut model with colors.jpg


Cut UV colors.jpg
 

frank beckmann

Well-known member
But looking at that curvy element, that is too curvy for 3mm hdf, maybe 0,8mm of wetted plywood will work...
Just experienced MDF user here. Bending 3mm board is quite easy but holding a certain curvature is not.
Prep for the board: It should have a little overheight and each top and bottom of the edge have sturdy wooden strips glued to its back. Take a 120g/qm high quality drawing paper and wet it till it lays absolut flat and will not buckle+ expand anymore - dampen with a towel till it´s dry to the touch.
Now you can paste the paper with wallpaper paste or vinyl glue and paper the MDF board. Bend it instantly into shape and hold the curve with several lashing straps. Let the whole thing really dry out for a day or 2 before you remove the straps:
BentBoardSmall.png
 

GS089

Member
@ZooHead Great, but you have to do it step by step, because otherwise it could be confusing it cheetah does not place it one element after another... ?
@frank beckmann That's cool, yes that could work, but one curve is nearly 90grad, we will see.. that curve elements are made of four pieces, so its a closed box which can have frames inside to stabilize everything.

Here are some screenshots of the steps:

Bildschirmfoto 2022-05-17 um 10.17.44.pngBildschirmfoto 2022-05-17 um 10.17.56.pngBildschirmfoto 2022-05-17 um 10.18.08.pngBildschirmfoto 2022-05-17 um 10.18.24.pngBildschirmfoto 2022-05-17 um 10.18.45.pngBildschirmfoto 2022-05-17 um 10.19.07.pngBildschirmfoto 2022-05-17 um 10.19.25.png
 

Helmut

Well-known member
* As said by Frank B in posting #48:
* I suspect that maintaining the curvature on the intersecting bits of the spline-based "wings" will be a quite tricky part. You get in these intersections all sorts of fairly complex curves.
* Possibly, most of these are curves which are the result of an intersection 2D-plane x conical surface, so they are arcs of an ellipse / a parabola / a hyperbola. However, your screenshot implies that there is also an intersection of two "wings".
* Presumably this will all depend on the actual construction of the physical model. An obviuous trick would be to have stabilising diaphragms at the location of the kinks which maintain the curvature.

;) Servus aus Wien
 

Helmut

Well-known member
* In the case of two cones (or fragments thereof) intersecting you get quite complex non-planar curves. Probably quartic, but I would need to research that. This may be a major constructional PITA.

Screenshot 2022-05-17 at 18.55.10.png
Screenshot 2022-05-17 at 19.07.07.png
 
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