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Problem with SDS
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Problem with SDS // Archive: Tech Forum
Post by splinters // Jun 23, 2006, 10:33pm
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splinters
Total Posts: 4148
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I should know the answer to this-been using TS7 long enough but can anyone provide a quick answer. I am making a raincoat for Harold (see Harold thread) but when I apply SDS, the top and bottom are forming a sort of half cap (joining to a point in the middle). Any idea how to fix it? It sarted from a cylinder that had boolean applied to remove the necessary bits. Should I have started with a spline polygon here rather than a booleaned primitive? |
Post by GraySho // Jun 23, 2006, 10:45pm
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GraySho
Total Posts: 695
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Booleans often leave problems on the topology of the mesh, so I guess that's what caused the problem. |
Post by Tiles // Jun 23, 2006, 10:47pm
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Tiles
Total Posts: 1037
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Have you tried to add an extra edgeloop at the edges of the cloth? |
Post by Alien // Jun 23, 2006, 10:56pm
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Alien
Total Posts: 1231
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I should know the answer to this-been using TS7 long enough but can anyone provide a quick answer. I am making a raincoat for Harold (see Harold thread) but when I apply SDS, the top and bottom are forming a sort of half cap (joining to a point in the middle). Any idea how to fix it? It sarted from a cylinder that had boolean applied to remove the necessary bits. Should I have started with a spline polygon here rather than a booleaned primitive?
I'm assuming that when you say you used boolean subtract, you did 2 operations - 1 for the middle of the cylinder, & another for the opening at the front? I just tried this, & admittedly with a much lower detail cylinder, but yeah, the SDS did cap it, but there's nothing to stop you editing the SDS mesh, just as you would a normal, non-SDS mesh.
For example, at the bottom of your coat cylinder, just delete the centre vertex, then make any other adjustments to the SDS mesh as needed. |
Post by GraySho // Jun 23, 2006, 11:04pm
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GraySho
Total Posts: 695
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There's a workaround to create the same shape without booleans. Add extra faces on top an bottom of the cylinder (polygon bevel), then delete the inner caps. Connect the the inside of the caps from top to bottom with add edge tool. you'll get a hollow cylinder. Add more edges where you want the cylinder to open, and delete the edges. |
Post by splinters // Jun 23, 2006, 11:11pm
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splinters
Total Posts: 4148
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Just tried this by drawing the outline with the polygon tool, so basically a very thin C shape. Same thing happened.
I just want to smooth the basic poly shape I have-is there a simple way of getting this shape I need without editing the SDS mesh |
Post by GraySho // Jun 23, 2006, 11:26pm
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GraySho
Total Posts: 695
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Tried it as well with an extruded C-shaped poly curve. Looks like a bug in the sds system. Even when I'm adding an extra face on the caps with the polygon bevel tool, the topology is screwed. I added and removed a sds layer and suddenly weired new geometry was added. |
Post by Alien // Jun 23, 2006, 11:39pm
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Alien
Total Posts: 1231
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Splinters: Yes there is, gimme 1/2-1 hour & I'll post an explanation [need to go have a bath].
GraySho: Nope, no bug, see my response to Splinters, I'll explain in a while. |
Post by splinters // Jun 23, 2006, 11:49pm
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splinters
Total Posts: 4148
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Cheers Alien-this is bugging the life out of me this morning...:(
Ain't too proud to beg...;) |
Post by GraySho // Jun 24, 2006, 12:16am
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GraySho
Total Posts: 695
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Well, Alien, if sds creates geometry where it shouldn't, it sounds like a bug to me. No matter if it can be fixed or done with a workaround. |
Post by splinters // Jun 24, 2006, 1:17am
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splinters
Total Posts: 4148
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It has been confirmed as 'not a bug' but also slightly unexpected behaviour. Either way-Parva kindly supplied the answer; |
Post by Alien // Jun 24, 2006, 1:29am
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Alien
Total Posts: 1231
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It has been confirmed as 'not a bug' but also slightly unexpected behaviour. Either way-Parva kindly supplied the answer;
Damn, he beat me to it! :o
I was just working on making screenshots to go with my explanation. :)
I was also going to add in response to GraySho's last post that it's not a case of tS adding geommetry where it shouldn't with the SDS, but of the user not adding geommetry where they should, prior to using SDS.
Splinters: there's another way to do it as well:
Start with a Rounded Cylinder primitive
Copy
Scale the copy smaller uniformly in all axis [axes?]
Scale the copy larger in the Z axis
subtract taller cylinder from smaller cylinder
Go into point edit mode [still in poly, before SDS]
Select Point Edit: Faces [as opposed to the context 1 that selects anything]
Highlight the faces that you want to remove - inner & outer, as well as upper & lower
Click delete vertices
Apply SDS |
Post by GraySho // Jun 24, 2006, 1:35am
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GraySho
Total Posts: 695
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Good to know :rolleyes: I just tried another thing. Create a cylinder and subtract another cylinder to get the hollow one. Without opening the cylinder on the side, add and remove a sds layer. tS creates those edges on the caps automatically. |
Post by splinters // Jun 24, 2006, 1:58am
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splinters
Total Posts: 4148
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Cheers for all your effort guys-plenty here to help anyone else who might get stuck as well. I really appreciate it and so does Harold-it just started raining again...;) |
Post by chrono // Jun 25, 2006, 6:44am
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chrono
Total Posts: 0
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Splinter tell Parva that it's expected behavior because the faces 'center'/axis was averaged in this case and since the catmull uses the faces 'center' it's correct. I cross checked this with SILO and got the same results, so it's the Cat-Mull equation.
But you'll also get the same effect when you use Tip, SmoothQuad, Scale, Rotate, Move, All extrudes, hell virtually any poly tool in TS that uses faces. |
Post by splinters // Jun 25, 2006, 7:04am
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splinters
Total Posts: 4148
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Splinter tell Parva that it's expected behavior because the faces 'center'/axis was averaged in this case and since the catmull uses the faces 'center' it's correct. I cross checked this with SILO and got the same results, so it's the Cat-Mull equation.
Ironically Chrono, it was Parva who said it was expected behaviour...;) |
Post by chrono // Jun 25, 2006, 7:40am
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chrono
Total Posts: 0
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*shrugs*
YOU mis-quoted him and since I had only what YOU wrote to go on.... :rolleyes: |
Post by splinters // Jun 25, 2006, 7:58am
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splinters
Total Posts: 4148
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Chrono-it is not that important...:) Anyways I said:
It has been confirmed as 'not a bug' but also slightly unexpected behaviour. Either way-Parva kindly supplied the answer;
Parva did not confirm it as a bug...a developer did...sort of...but we have laid that one to rest now anyway...:cool:
So it is expected behaviour in an unexpected kinda way...:rolleyes: |
Post by rj0 // Jun 25, 2006, 9:03am
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rj0
Total Posts: 167
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Very helpful! Great 'detective work'.
rj |
Post by Alien // Jun 25, 2006, 9:11am
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Alien
Total Posts: 1231
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OK, read the first page of response, didn't click to the next page (to see the answer) and came to the same conclusion. Oh, well.
If you're not on dial-up, you could set number of posts per page to 40, 10's just the default. :) |
Post by chrono // Jun 25, 2006, 9:17am
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chrono
Total Posts: 0
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Since it was known behavior there can be no such thing as the unexpected behavior. Because if it's unexpected then it's not a known.
*BTW why were you using a cube-like object for the raincoat anyways? Style?* |
Post by splinters // Jun 25, 2006, 9:44am
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splinters
Total Posts: 4148
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Raincoat started out as a C shaped polygon which was extruded repeatedly, giving me several loops to grow and shrink before applying SDS. End result, while not everyone's way of doing it, turned out exactly as I envisioned...:)
Thanks to all who helped me get it sorted...:D |
Post by hemulin // Jun 25, 2006, 10:10am
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hemulin
Total Posts: 1058
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Hmmm, so there's a hand-less body out there somewhere :confused: |
Post by Alien // Jun 25, 2006, 10:15am
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Alien
Total Posts: 1231
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Hmmm, so there's a hand-less body out there somewhere :confused:
LOL. It kinda reminded me of how some mothers used to sew gloves/mittens to a string/chord/whatever & that in turn to the inside of their kid's coat sleeve, to stop them losing the aforementioned gloves or mittens. |
Post by hemulin // Jun 25, 2006, 10:23am
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hemulin
Total Posts: 1058
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LOL. It kinda reminded me of how some mothers used to sew gloves/mittens to a string/chord/whatever & that in turn to the inside of their kid's coat sleeve, to stop them losing the aforementioned gloves or mittens.
Yeah, fortunately my mother wasn't like that. I bet it would be a bit of a pain in the summer though, having to have either mittens on or have them stuck by your wrist, and in that heat :eek:
However those 'gloves' look pretty realistic. |
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