fixing normals in lightwaves

Moderator
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Post: #1
alright, so all my normals are now flipped into the right side, but they are facing the wrong direction (aka, non perpendicular to the triangle's plane).
ideas!
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Oldtimer
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Post: #2
Not quite following you... an example, perhaps?
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Moderator
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Post: #3
(previous message got deleted, bloody crappy quick reply)
anyways, imagine a sphere with light source on the right. Normally you would expect to see a smooth gradient of shadowing. from right to left. But instead of the normals being outward and perpendicular, on mine, they are outward and randomly pointing, so instead of a smooth gradient, I am getting splotches of color/shadows in all the wrong place.
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Member
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Post: #4
If you have triangle ABC then the normal is (B-A)X(C-A) and then unitize the result. If you want smooth shading then for each vertex take the normals of every triangle that contains that vertex and add them all together and unitize that result. What are you doing instead?

Why ask a question where there is clearly something specific in your code thats gone wrong - but you dont post your code - so everyone should just take guesses as to what *might* be going wrong?
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Post: #5
Are you using an object that has been created in Lightwave in some other application or are you trying to render the object in Lightwave?
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Post: #6
This isn't code, this is Lightwave, codemattic.

Cloister: The object was created in lightwave by creating a polygon (roughly quarter circle) and the spinning it around the y axis.
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Post: #7
I'll try doing the same in Lightwave later tonight and see if I can give you any further tips.

Did you try posting something to the Newtek forum as they are usually very helpful?
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Member
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Post: #8
skyhawk Wrote:This isn't code, this is Lightwave, codemattic.
sorry for snapping - I should of noticed that you posted in 'Art and Audio' and not in 'Programming.' If you will eventually import it into your own app you could rebuild the normals yourself of course. If you are rendering for sprites or something, sadly, I cant help since I dont have LW.

But the same way you could post code when you have a programming problem - you could post the lightwave file of the object that you cant get the normals to align correctly. Maybe someone who had/knew LW could figure out the problem quicker that way. Or a screenshot showing where/how things go wrong.

My issue is that very often (at least in the programming section which is the only topic I know anything of) people post questions that are maddeningly vague. Im just trying to think of ways to better define questions and problems and so get quicker and more accurate answers.

good luck wrangling those normals,
Codemattic
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Post: #9
here is a picture of the problem:
[Image: normalprob.jpg]


EDIT: Well, I don't know why it worked, but I started clicking buttons. And I clicked "Spin Quads" and that apparently did the trick.
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Post: #10
skyhawk Wrote:here is a picture of the problem: <snip>
I don't know if you caught my post in the temporary forum, but your picture seems to confirm what I suggested: I think your lathed object is slightly crossing over itself, and any polygons which cross the axis of revolution are affected but the rest aren't.

You might be able to avoid this problem by doing the lathe operation a bit differently. If Lightwave allows you to do this kind of thing, try snapping the lathe axis to the bottom vertex of your source shape to ensure that no part of the shape crosses the axis. Alternatively, do the whole thing with the aid of grid snap.

BTW, what is the source shape? A quarter arc? A semicircle? Open or closed?

Neil Carter
Nether - Mac games and comic art
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Post: #11
NCarter Wrote:I don't know if you caught my post in the temporary forum, but your picture seems to confirm what I suggested: I think your lathed object is slightly crossing over itself, and any polygons which cross the axis of revolution are affected but the rest aren't.

You might be able to avoid this problem by doing the lathe operation a bit differently. If Lightwave allows you to do this kind of thing, try snapping the lathe axis to the bottom vertex of your source shape to ensure that no part of the shape crosses the axis. Alternatively, do the whole thing with the aid of grid snap.

BTW, what is the source shape? A quarter arc? A semicircle? Open or closed?

it wasn't overlapping, this I am sure of (only made it do 360∞Wink

the source shape was roughly a quarter arc
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Nibbie
Posts: 2
Joined: 2009.01
Post: #12
among other issues, when it looks like that and some polys are dark, etc, ty using merge points (m) and that ussually does it. if the normals are screwed its ussually cause there are too many points in the poly, even if it looks like a triangle, if there are more than 1 point in any of teh corners it is likely to mess it up.
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Post: #13
I haven't used lightwave for a while, but I remember a reduce-complexity filter-thingy that usually had great results for weird stuff like this. Hope I'm not wasting bytes

-Jon
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Post: #14
whogben Wrote:among other issues, when it looks like that and some polys are dark, etc, ty using merge points (m) and that ussually does it. if the normals are screwed its ussually cause there are too many points in the poly, even if it looks like a triangle, if there are more than 1 point in any of teh corners it is likely to mess it up.

I am 100% certain that these are 3 point polys


second thing. My models that I am making. They are not good. Apparently I can't export my models to 3ds format cause I have "polys with only 3 points". also, whenever I load them as .obj in bryce, it claims it can't. So I'm thinking I might have something wacky here. Any ideas why my models aren't liked? I could put one up for yall to try and see
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kberg
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Post: #15
Yeah, put up a .lwo of one that's giving you problems, and I'll give it a look over if you want.

I've found lightwaves .obj exporter to be adequate, though pretty basic; so I'm not sure what could be choking bryce..
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