Problems with reverse faces and textures
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Here is a very basic example. Note that you can often get into a situation where there is a closed loop of coplanar edges (this one is just too obvious). Often these edges are hidden or softened so you sometimes cannot even see them on the surface.
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Dave R and I are in the same time zone. Thanks, Gaieus, for explaining "re-skin", while I slept. I didn't spell it right, but you explained it.
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@mitcorb said:
Thanks, Gaieus, for explaining "re-skin", while I slept. I didn't spell it right, but you explained it.
I did not even notice it. I should have been sleeping as well though.
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Many thanks, Gaeius and DaveR for the excellent advice.
I downloaded the example "InsideFace.skp" provided by Gaeius and was wondering how did you get those colored lines the ones in Red and Yellow, when I draw it always defaults to Black. Is this linestyle also present in the "Styles" palette?
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Give the edges you want 'colored' different colored materials [Entity Info let's you change the selected edges' materials en mass] and then use a style that displays edges 'by material' and not by the default 'all same' [color = 'black']...
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Exactly.
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I also had the problem of reversed faces. There seemed to be no consistency with how I could draw and maintain a front face all the time. At first I used the "R" key shortcut with the push/pull tool to reverse faces, but that got tedious.
So my (first) solution was to make the front and reverse faces same white color, so it no longer mattered (or so I thought). When I exported a model to the warehouse that was colored different on both sides the result was horrifying. I had to bring it back and fix all those reversed faces.
Now I simply make both sides SAME COLOR/TEXTURE. More work, as I have to color each face twice. SU will not color both sides at once. (
Why not ) The only major drawback is when I have a missing face in a sea of same color faces..... that missing face is hard to find. And in the rare case where I have 2 different colors on front and back faces, the face reversal problem is still there.What I cannot understand is why SU will not maintain face directionality while I draw or view the model, but seems able to get it right when I export a model to the warehouse. If SU will correct face directionality on export, why can't I have a button to do it right now, in the model?
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@jgb said:
So my (first) solution was to make the front and reverse faces same white color, so it no longer mattered (or so I thought). When I exported a model to the warehouse that was colored different on both sides the result was horrifying. I had to bring it back and fix all those reversed faces.
A bit like putting a piece of black tape over the Low Oil Pressure warning light, huh?
@jgb said:
Now I simply make both sides SAME COLOR/TEXTURE. More work, as I have to color each face twice. SU will not color both sides at once. (
Why not ) The only major drawback is when I have a missing face in a sea of same color faces..... that missing face is hard to find. And in the rare case where I have 2 different colors on front and back faces, the face reversal problem is still there.I think it would be a lot less work to just fix them as they occur. Make the back face color something that will be very obvious so they are easy to see.
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@dave r said:
A bit like putting a piece of black tape over the Low Oil Pressure warning light, huh?
I think it would be a lot less work to just fix them as they occur. Make the back face color something that will be very obvious so they are easy to see.
Re: the tape. Good idea. My check Engine light is always on.
(Actually I know what the problem is. A $2.00 part in my emissions control valve is leaking. It would cost $600 to fix, as they have to take the exhaust manifold off to get to the valve body beneath it. It ain't at all serious and my car (97 Camry XLE) passes emissions tests with very wide, nearly new margins.)As for reversal correction as I work, to fix them as I work is a lot more work than same colour both sides, (as most of my faces stay white) except where the 2 sides may be different colours and I want to export the model, which is rare. Besides, why shouldn't SU do that for me?
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Black tape on the check engine light will probably be just fine. Maybe. I hope.
I don't find that I get reversed faces all that often when I work. And fixing them as I go isn't that big of a problem. I just right click on a properly oriented face and choose Orient Faces. I do see if frequently in models by other folks who start with flat surfaces divided into smaller faces and then use Push/Pull on them. Of course in those cases, while it looks like the faces are reversed, SketchUp is doing the correct thing if you look from the other side.
As was already mentions, internal faces can cause problems but those should probably be removed anyway.
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