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View Full Version : BUG! CC subpatches don't render properly with shadow maps



stib
07-27-2006, 11:36 PM
I've been going insane trying to work out why my scene won't render properly, and I've finally caught the bug. (What were all you beta testers doing?).

Like any red blooded lightwaver with a new copy of 9 the first thing I've done is go crazy with Catmull Clarke n-gons. Perfectly understandable after years of painstakingly making sure there's never any polygons with more than four sides in my objects.

But there's a bug when you try to render them with both shadow mapped lights and fields. If you have a scene with:CC sub-patched objects


and you are using shadow mappped lights


and you are rendering with fields


and you are not caching your shadow maps

then shadow mapped lights will not work the second (and subsequent) AA pass. This means that your scene will come out a lot darker than you expect. You can actually see it happening in the render preview window; the first pass will be fine, the next will go all dark on you.


here's a couple of tests: on the left with a raytraced light, and on the right a shadow mapped light:
http://www.pureandapplied.com.au/images/pngs/raytraced.png http://www.pureandapplied.com.au/images/pngs/badRender.png

these images used PLD 5 pass AA with Mitchel reconstruction (I've tried classic AA and it doesn't work either), Classic camera (again, classic or perspective camera doesn't affect it either) Lower field first (ditto with field order, only turning fields off fixes it) no motion blur, no DOF.

This is very reproducible: attached is a scene and objects if you want to try it out for yourself.

Can we get a Newtek response, because it means no shadow mapped lights for those of us who work in television and need to render fields (no, let's not start that debate).

When is there going to be a bug sticky on this forum? Mighty hubristic of them not to have one already..

RedBull
07-28-2006, 12:05 AM
So the subpatch scene works fine, and the only difference is CC patches in the scene?

I also notice while bugtracking an MD issue, i notice that CC doesn't work at all with Motion Designer. I was hoping for better deformations.

I'm sure there will be quite a few tools that did not make the transition from the old to the new. It would be wise to use SubD's for production for a little while i would think.

PS: Obviously rendering fullframes and use fields in FCP or similar is the temporary workaround, or subD's.

stib
07-28-2006, 12:20 AM
Hey! that's one variable I didn't try. Well done that player.

I just tried it now and the bad news is that it's not just CC subpatches, it's ALL subpatches. This is looking grim.

So using standard subpatches is out too. Did no-one do a render with subpatches, fields & shadow maps in all the months thay had it in beta? Again, what were the beta testers doing..?

The workaround I'm using at the moment is to freeze all my objects. To get proper fields I'd have to double the frame rate and that would blow my render times even more out the window (that's why I'm using shadow maps in the first place, instead of nicer raytraced area lights). Freezing works but it's a PITA for my workflow. This needs fixage doublequicksmart.

Karmacop
07-28-2006, 12:40 AM
So using standard subpatches is out too. Did no-one do a render with subpatches, fields & shadow maps in all the months thay had it in beta? Again, what were the beta testers doing..?
Have you ever written or tested software before? With something as complex as Lightwave bugs will always get through, especially bugs like this where it's several specific things interacting.

stib
07-28-2006, 12:52 AM
maybe it's just me, but patches, fields and shadow mapped lights are for me what bricks, mortar and bog are for a builder. The very first scene I did in 9 had them in it.

If you're rendering animations for the telly, you need fields. If you want better shadows than normal raytracing, and you don't have the render time to go with area lights what do you do? It's not like I'm doing anything extraordinary.

Oh BTW: have I ever written software? Check the sig.

jameswillmott
07-28-2006, 12:57 AM
Turn Motion Blur on, it will solve the problem for the meantime.

stib
07-28-2006, 01:18 AM
Turning motion Blur on works in that test scene, but not in the scene that I'm working on (...?). I had MB turned on when I discovered the bug.

[edit]Whoops, I forgot that there are now two places to turn on MB. I had it on in my globals, but didn't have it on in my camera. Yep that seems to be working. Whew.

Fanks.

Karmacop
07-28-2006, 08:52 AM
maybe it's just me, but patches, fields and shadow mapped lights are for me what bricks, mortar and bog are for a builder. The very first scene I did in 9 had them in it.
I understand, and I hope I didn't come off too harsh. I'm amazed it wasn't caught too, especially with the open beta.



Oh BTW: have I ever written software? Check the sig.
What can I say, I'm sorry :)

pureandapplied
07-29-2006, 05:45 AM
no worries mate. I must admit that my software is chock full o bugs, but then again, nobody pays for my software. I think I was just subconsciously hoping that all the lighwave problems would be fixed in 9, and it really annoys me when things that weren't broken are now broken. Doesn't look like LW9 is the Release That Saves Lighwave From Obscurity, even though I hoped it would be.