Mesh seams question?
Blitz3D Forums/Blitz3D Programming/Mesh seams question?
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| I've been writing a 2d in 3d landscape creator with the help of Fredborgs polygon tesselate function in the archives. Once the mesh is tessalated I use a welding function to ensure there are no unwelded verts. In this image you can see the background slightly which is quite annoying - see thin line from left to right. A similar thing happens sometimes if you addmesh two cubes - a seam sometimes appears. Has anyone experienced this or know of a solution to prevent it. I'm pretty sure it isn't a driver issue as I've not updated these for years but open to suggestions. Cheers Stevie  |
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| Seen this a lot. "Hairline cracks" Make sure your vertices are welded. Unfort. using an other CLS color doesn't seem to fix it IIRC. A rounding error problem with DirectX. It may or may not help if you alter the quality/speed settings of your card.  Tho, strange, my dots are black on white, yours white on black. It's a conspiracy to drive us insane. |
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| Yep, I've had this before. It only seems to happen when two separate, planar polies (that don't share any verts) have a common edge. Cubes have separate polies that share edges but we dont see this effect, presumably because the polies involved aren't planar?! I'm not really sure why this makes a difference, TBH. Other than trying to get rid of them by setting the CLS color to black, I don't know of any solution. BTW, if your level is just going to be flat black as shown, I can't see why you have a seam at the place shown? [edit] Just had a thought. You may be able to get rid of the effect by doing a 2 render pass of the level mesh: do a wireframe render before doing the regular render. Might work. :) |
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| Thanks folks - I thought it was just me and it is indeed a pain in the arse! It would make sense that it's a DX thing. I had experienced this sometimes with my vehicle engine but as I use vertex colours and flatshading it is necessary for me to unweld all polys so I'll just have to live with it. The level mesh will be all black with a sky texture covering the background so cameracls won't help me. BTW, if your level is just going to be flat black as shown, I can't see why you have a seam at the place shown? If you see the wireframe version it makes more sense as you can see the bizarre ( but correct ) way that Fred's function builds the poly's. Sometimes there are no seams sometime there are none. An interesting thought re 2 render passes big10p - wireframe rendering is sloooow though. In a similar vein I thought of unwelding all the tri's again but extruding each vertex slightly away from center so that I get a very small ( but unnoticable ) overlap. I think ( hope ) it will work for me. I'll post back with results. Stevie |
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Yay, it worked a treat!!! Cheers Stevie |
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| Congrats. Unfortunately, in a 3d scene it isn't so easy. |
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| Unfortunately, in a 3d scene it isn't so easy. It is a 3d scene as the landscape has some depth too. I did something similar to some of my vehicle meshes which had cracks and it works just fine so I can't agree. Sure, it may not work for ALL meshes but if you fiddle with the offset I'm sure you could get it looking reasonable. Stevie |
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| An interesting thought re 2 render passes big10p - wireframe rendering is sloooow though. Yeah, I was thinking just render the level mesh in wireframe, which I thought probably wouldn't make too big a difference to the render time.Anyway, glad you got it working. ;) |
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