View Full Version : Rendering funnies

05-03-2003, 03:35 PM

I have a strange problem with shadows, in my Playstation 2 model there are"notches" appearing in the shadows, even though the edges are straight.

Any ideas? The model was trippled even though there were no non-planer polys - just in case.

You can clearly see that instide the letterinh, the shadows are "notched" like the edges arent straight.

Everything is Raytraced..shadoiws, reflections etc...


05-03-2003, 04:17 PM
Not sure but it might came from smoothing. Try to uncheck "Smoothing" box on appropriate surface if it's checked and try to render without it.

05-03-2003, 04:54 PM
Nope, not that - tried, had no effect. Although... if it was, Id be real upset... thats a basic feature... Glad it works :D

05-03-2003, 08:26 PM
If your light is placed in the direction of and under your camera those shadows (with notches) seem correct. Set the viewport to Light view and have a look.

John Fornasar
05-03-2003, 10:18 PM
Try these:
You might have some crossed vertices/points
or Non-planar polys

could you post a few close-up wireframes (get right down to the letter), it'd be easier to figure it outl...

going back to Scolopendra's post - Smoothing works, but there is a time and place to use it. You'll get some funky effects if you click it on certain flat faces.

one more... it's not necessary to automatically triple your poly's if you are not going to displace them.

05-04-2003, 02:01 AM
Okay... heres a couple of wire images....

05-04-2003, 02:02 AM
And another....

05-04-2003, 03:01 AM
Actually... Im just looking at this again, and wondering if its correct...

If you look at the "2", could the "notch" be the inside edge (or lower edge) being cast?

The reason this came up, is because on a CUP I was doing, I got the same problem (sub-d), but when I froze to a very high level, it went away... It was on the rim, and looked exactly the same as this, but with no excuse...

But, with this one... Im wondering if its actually an artifact of the inner sections, casting on the outer rims... The "o" from is another example... 2 notches... this would be consistant with the inner part being cast wouldnt it?

I was expecting a smooth shadow all round... perhaps thats not what you get though....

Elmar Moelzer
05-04-2003, 03:09 AM
Hey Bigboy
Try trippling the object and see if the problem persists.

05-04-2003, 03:12 AM
Heres the image that started me thinking about this... perhaps this is a better example anyway...

IfI freeze the object, it still does it... however, if I freeze it with a very high sub-d level, it fixes it... I guess hides it is closer the mark.

05-04-2003, 07:26 AM
looks to me like it's supposed to be that way. seems too uniform to be an error. try moving your lights and see if the notches move as well.

05-05-2003, 06:42 AM
.... deleted due to cluelessness :)

05-05-2003, 06:50 AM
Actually, I think the shadows are right. I've drawn lines from the geometry I think is casting it to the shadow. They all seem consistent.

05-05-2003, 10:21 AM
Yeah, I was begining to think that as well... although "odd" it looked right...

What about the reflection in the cup though? I cant figure ANY reason for that

05-05-2003, 11:21 AM
Does the flaw in the cup always stay in the same place, no matter what the lighting and camera position? Have you checked for 2 point polys and such?

05-05-2003, 12:35 PM
Yeah, seems to stay in the same place.... moved the lights and the camera, still there.

There are no "funny" polys. All are 3 or 4 point, all planer.

As I said earlier... if I freeze it at a "very" hi level, it goes away..


Actually... if I move the camera... it moves, like its attached to the cup somehow.

05-06-2003, 07:27 PM
On the playstation model, the shadows look correct to me, if you did a short animation while panning the light, you'd see the notches move consistently.

The Mug is more of a puzzler ... try turning off reflection/refraction/caustics and see if it's indeed a notched shadow. Sometimes these other settings can confuse the issue.

My 2 cents, you may have some change coming.

05-07-2003, 12:19 AM
Well, theres no refraction/caustics... and if I turn off reflection, it all goes away (since its a notch in the reflection), but thats no use.

I can turn off ray trace shadows, refraction and transparancy... and its still there... with reflection off, it goes away... which isnt a surprise, since thats where the problem it :)

So basicaly, its a notch in the reflection calculation... somehow.. if I drop it to x2 recursion (lowest level) its still there.

Once frozen, the normals look right.. so its not like its a funny pointing face either...

05-07-2003, 12:27 AM
Well it could be flaky way the poly's are rendered, but being a reflection, I'd try to rule out what's being reflected. Are you using a reflection map? If that's not it, try setting a fixed backdrop color, and if it still doesn't go away, animate it rotating 20 degrees just to see if it's messing up the reflection of the opposite rim, or if it's a distortion in the mesh. I'm guessing that if it's a bad reflection, it will stay in the same place as the cup rotates. If it's a distortion in the mesh, it will likely move as the cup rotates.

I'm just guessing though, I'm no expert, just trying to be helpful.
Hope you can find it.

05-07-2003, 05:54 AM
You know, I almost wonder if it's not something to do with the handle of the cup. Try removing the handle of the cup and run a test render.

05-07-2003, 11:59 AM
Nope... removed the handle, and its still there...

When I rotate the cup, the "notch" moves with it... So on first inspection, it would look like a piece of geometry is messed up... but if it is, I cant see it... and if it is, then freezing to higher levels should exaggerate it, not fix it...

I did freeze it so I could see the normals of the polys it makes, they all seem correct, and uniform.