Sketchup optimization of the model.
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Hollow objects and unwelded verts / edges.
I have been looking at models made with sketchup.
The models made with it have double sides, if one made a box, it makes the inside as well, so rather than having 6 faces, it has 12, everything it makes is hollow,nothing is attached, its made from lots of faces, its not a solid model, this makes the model way larger in size, I'm looking at exporting sketchup models out into other 3d applications.The whole model needs welding of the edges or vertex, this can be done in other aps though perhaps this will mess up the texture UVs, I'm not sure what to do about the hollow model problem, sketchup is great but it has a problem with optimization, the models are hollow so it doubles everything, plus the edges or it could be the verts are separated so they need welding, what are the options one can do to have better optimization and not have these floating sections of the model and have them be solid and not hollow models.
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There isnt really a lot you can do about the whole hollow model thing, as SU is a polygon modeller and so doesnt work in solids.
You dont need to worry about doubling the number of faces though, put simply that just isnt the case. A cube will always have 6 faces in SU.
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SketchUp is a surface modeller, so it's not surprising that it produces hollow models. However it doesn't have twice the number of necessary faces, because each face only has one normal and it is inadvisable to allow the blue reverse face to be shown unless it is absolutely unavoidable. This is because of resulting problems with certain renderers. Therefore a cube still has 6 faces not 12.
If, on the other hand, that cube is exported to 3ds it will have 12 faces because each square face will need to be triangulated.
This "hollowness" only really a problem if you are exporting to a solid prototyping machine...when you need to ensure that the entire surface of the mesh is completely closed. But SU models can be exported into .stl or similar formats and there are posted examples of the resulting real-world models.
I'm not sure what problems you are having exporting to other programs, but I make models for a living and we routinely export to all manner of different formats including 3ds, dwg, obj, lwo and dae (Collada) without much difficulty. I have to say that in terms of faces and file size, the SketchUp version is often the smallest. This Director's chair I did over the weekend only has 617 faces in the SU version, it has 2,424 in Max...although the Max file is smaller at 73 KB against SketchUp's 102.
When exporting, you need to ensure that the options are set according to your needs. You can export only the faces...or you can also export all the edges. Similarly, you can weld all the vertices or you can maintain the UV coordinates in .3ds. It's not possible to do both with .3ds; it's such an old, antiquated format that it can't handle both.
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The only difference with SU and most other 3D software is that SU allways display the backface. You can do this in most other applications as well, you just have to enable it.
SU automatically welds geometry together when it meets. Unfortunately there isn't any function to weld together nearby geometry. That's why it's important to ensure everything snaps correctly when you draw.
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Being triangulated is fine, I want to export models to a video game engine, I need them to be as efficient as possible, the file I need is .x, the plug in for SU to export to directx messes the scale so I exported as .3ds (I can use any file format as I have programs to swap file formats to any file type, so I am not limited to .3ds) then in another app I welded the vertex and exported to .x, but I want to have my model as efficient as possible, whats the best thing to do.
Can you weld the vertex in SU, I had a model that was841 faces, 1842 edges, and 1170 vertex, I exported to a 3d app, welded the vertex, it was then
841 faces, 1364 edges and 511 vertsvertex came down a lot, would of thought the edges would come down more. I am not sure if it kept the UVs correct, Id have to test. Would be nice weld the vertex in SU, or on export have them clean up.
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Note that there are some quite oddly-working 3DS export options. The "export standalone edges" option takes every visible SU edge and adds a thin slice of a face to the exported file. I understand this is meant to make it possibre to reproduce the SU look in other applications, but it makes smoothing and rendering the file a mess. This used to be checked by default, and confused a lot of people who did not know where to look (behind the Options button in the Export File dialog box).
Anssi
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I had the "export standalone edges" option checked, so unchecking that will bring the model complexity down, I see it has weld edges, now I want the edges welded, as for it messing up materials, I want to keep the texture placement, will it mess that up, what if I weld it in another 3d aplication, does welding edges mess up the texture placement? Ill do a test and find out.
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It's hit and miss whether welding edges will mess up the UV mapping. It does more often than not. You can weld them in Max, but the procedure is so lengthy and complicated...messing about, back and forth with smoothing groups...that I've forgotten how to do it. Generally, I just avoid 3ds export with mapped models and go with another format..
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I tried the export 3ds and weld edges, it messes up the textures, not sure if that can be corrected quickly in another 3d app, as in its just a click, align face mapping, or something, or if one has to compleatly re alighn the texture.
I tried exporting as 3ds and not welding edges, I then opened it in deled, you can weld all the vertex at a click of a button, I get good settings on 0.25, I then opened it in another 3d app, the model is faceted, as in one can see the cross sections, ie the triangulated line in some parts, so smoothing is messed up, not sure if that can be corrected, adding smoothing groups isnt something Ive done before, can the models be corrected of this odd triangulated effect, as it looks a bit rough with that going on.
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That is exactly right, and well described. .3ds is a bit quirky. You might look into deep exploration 3d (or something like that). I think its expensive, but it might do it correctly. Solo is a great person to ask about that I think?
But yes, you can re=apply the smoothing groups in 3ds max. But on large models, with lots of smoothed stuff, it is a bit tedious to do in 3ds max.
Chris
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Even if you succeed in getting a model smooth in Max, there's no guarantee that it will stay that way. I've lost count of the number of times I thought I had it cracked...only to save the model, open it again.........and find that it had reverted to being facetted again.
The 3ds format is positively diabolical that way...which is why I don't go down that route. I have Deep Exploration too; it doesn't help with that issue. Not even converting straight to .x format from skp (which is possible); the mapping is generally still screwed. Geometry-wise, SU is fine, but it has a UV mapping system all of its own.
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@alan fraser said:
I have Deep Exploration too; it doesn't help with that issue.
Now I've lost all hope.......
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I have Deep Exploration also, its invaluable for games designers swapping between model formats, so I can export out and convert any model type just about, but I have a question, does exporting out in non 3ds formats as a straight model, then welding vertex in another 3d app result in faceted models, or is it only with any max files, is it possible at all to export a SU model, weld it in another program and not have a faceted model.
I just tried exporting with a obj model, doesnt seem the model has unwelded edges or vertex, I think this is just an issue with 3ds then, and that other model formats are fine.
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.3ds file export has the option to weld vertices, but this will lose pretty much all smoothing groups and material placement. Or you can choose to keep material placement, but thill will make SU not weld any vertices. So its often not helpful. I think some people use .obj export maybe?
Chris
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