creating mitre angles for faces

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robint
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Joined: Tue Sep 25, 2018 8:20 pm

creating mitre angles for faces

Post by robint » Wed Sep 26, 2018 1:53 am

Hi Stellas

I am joining the band of great stella users

I was impressed by the work on the london gherkin
viewtopic.php?f=2&t=69&start=30

One query raised by the OP was a means of generating dihedral angles on tiles (faces) to allow models to be finely assembled from wooden tiles - presumably sawn from say 3mm thick slices of exotic woods using an accurate saw table

I wondered if there was a way of generating these data - perhaps by shrinking the model and creating an inner but small duplicate
solid mitre.jpg
solid mitre.jpg (74.92 KiB) Viewed 1591 times
Image

Robin

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robertw
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Location: Melbourne, Australia
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Re: creating mitre angles for faces

Post by robertw » Wed Sep 26, 2018 1:38 pm

Yes, as follows:
  1. Set the scale of the model from the Scale menu (eg size of inner model)
  2. Put this model in a memory slot (Edit->Put Model in Memory, or type m1 to put it in slot 1)
  3. Set scale of model to another size (eg size of outer model)
  4. Add to model in memory slot (Edit->Add/Blend from Memory->Memory 1)
  5. To see that inner model is also there, either hide one outer face (Shift+Left-click to select a face, Ctrl+H to hide), or expand faces apart with Ctrl+Shift+Left-drag
  6. From here there are multiple approaches, but here's my suggestion...
  7. Hide an outer face
  8. Hide the matching inner face
  9. Toggle all face visibility with "Display->Toggle Shown/Hidden Faces" (or shortcut Ctrl+Shift+T)
  10. Now you see only the top and bottom face of the piece you're after (only the two faces we hid earlier)
  11. Hmm, would be very handy if you could take a convex hull of just the visible faces, but it doesn't do that. Maybe I'll add that later, so instead it's a bit tricky. You probably need to use Faceting mode
  12. Make sure you have at least two views (Ctrl+2)
  13. One should show your original model with only two faces showing
  14. Other view should show the Faceting Preview. Click in it to select it and use "View->View Models->Preview Faceting", or toolbar button Image
  15. You also need to enter Faceting mode, using "Selection->Mouse Selection Mode->Faceting Mode", or toolbar button Image
  16. You want the two existing faces as facets for your new polyhedron, so Ctrl+Right-click on each of them, and you should see them appear in the Faceting Preview window
  17. At first though, you'll see symmetric copies created too, so drop to "No symmetry" from the toolbar.
    Image
  18. The remaining faces need to be created by Shift+Left-clicking on each vertex around them and then Shift+Right-clicking anywhere to accept the facet. Do this for each of the remaining 4 faces. Should look something like this:
    Image
  19. Click the left-and-down arrow button in the top right area of the view. This makes a final model our of whatever's in that view Image
  20. Voila! You've made yourself a face tile

robint
Posts: 13
Joined: Tue Sep 25, 2018 8:20 pm

Re: creating mitre angles for faces

Post by robint » Wed Sep 26, 2018 5:04 pm

Hi Rob have ordered GS, DXF imports to SU with the cube as you suggest

Holy Batschwepps Batman, like all my birthdays came at once. This tiling will take some digestion once I get my lic key thru. Just the toy for those with too much time on their hands and 4k to blow on a cnc table

:P

Robin

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Peter Kane
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Location: S.E England

Re: creating mitre angles for faces

Post by Peter Kane » Thu Sep 27, 2018 6:28 pm

Yes, Rob is they boy wonder. Don't forget to post some pictures when you are done. Peter loves pictures.

Pete K

robint
Posts: 13
Joined: Tue Sep 25, 2018 8:20 pm

Re: creating mitre angles for faces

Post by robint » Thu Sep 27, 2018 7:29 pm

Here is another pic I wanted to post with my other reply but it wouldnt let me ?

I played with some of 3d distrotions in SU17 briefly also the hole creation and intersection of models
BTW in no way am I affiliated or trying to plug SU. It was mainly aimed at architects and furniture designers - and it was sooooo much easier than ACAD

I could knock up some rough 3d piping layouts in a heart beat - great for clash detection and beats building plastic models (huge time and cost )

But SU only does polygon circles so finding an intersection in space meant manual calcs, so dropping an icosahedron in SU is a breeze
icosa-1.jpg
icosa-1.jpg (96.54 KiB) Viewed 1582 times

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