View Full Version : How to disable Background Antialiasing?

06-30-2009, 04:48 AM

I'm in trouble with my compositing setting:
I've got a prerendered background, that gets its edges distorted whenever i render the scene. I found out, that it only works if i disable AA for the scene, what, however, is not a good solution.

How can i disable the AA only for the background picture, or what does the trick?


06-30-2009, 05:42 AM
Can you turn the background off, render it separately then add it in post.

06-30-2009, 06:51 AM
Well, i'd like to directly solve it in LW.

Sorry, i was wrong in my first posting, it has nothing to do with the Antialiasing setting, it is always distorted, AA just makes it worse. I also tried an oversized picture as background picture, but it didn't help either. I never noticed this problem, i'm rather puzzled right now.

It works perfectly with the new "Advanced Camera", but i cannot use it because it slightly changes my scene, and i have already prerendered stuff, so that the camera and its view must stay exactly as it is now.

edit: see the picture, this is just the background picture rendered again with all other objects turned inactive in the Scene Editor.

06-30-2009, 07:00 AM
can explain a liittle better...what's distorted?....the tree/sky map?

also what version/build of lightwave also 32bit or 64bit ans what o/s?

06-30-2009, 07:17 AM
The background picture, have a look at the edges of the shelf.

OK it looks like i solved the problem: changing the camera from classic to "Perspective Camera" (default settings) did the trick. I read in the Layout documentation papers "Persp. Cam" equals the classic cam for the most part, so i decided to give it a try and it gave me the exactly same picture as the classic, but without the aliased edges.

Still curious what's the problem with the classic camera though.

I once more attached two pictures to show you the problem.
The first one is "EmptySceneWithBackgroundPic_ClassicCamera.jpg", second one is "EmptySceneWithBackgroundPic_PerspectiveCamera.jpg".

Thanks so far.

06-30-2009, 08:35 AM
Is the pixel aspect ratio the same with both cameras? My guess is that you chose a video preset which uses non-square pixels.

07-02-2009, 01:48 AM
Are you using any of the (Soft) reconstruction filters or Gaussian? You don't want to use those with the classic camera, stick with classic reconstruction. I'm guessing that's why the classic render looks softer. The artifacts in the shelves may just be your classic cam settings are not high enough.

07-02-2009, 01:57 AM
Thanks for your suggestions, but none of them seem to explain the problem.

If you like, download the flawless picture ("EmptySceneWithBackgroundPic_PerspectiveCamera.jpg") set up a scene in layout, put it in for the background picture, set camera resolution to 990x600 and give it F9, and you'll see the problem.

07-02-2009, 03:24 AM
That is freaky-deaky! I'd try rendering another background but don't save it as a jpg, use something uncompressed. ( Jpg's SUCK for anything but going on the web ) That's all I can think of though. Ideally, lw should be able to return exactly the image that you put in the background, pixel-for-pixel. This could be a bug.

07-02-2009, 04:31 AM
Thanks for your confirmation. But even changing to PNG doesn't solve it.

Well, as long as changing the camera to "Perspective Camera" is a "workaround", it's not that bad, but yes, i think it might be a bug, too.

Try this pattern, it's 640x480, so you just have to load it and press F9.
The result with the Classic Camera is awful.

07-02-2009, 04:47 AM
Totally. I just tried it in lw 8.5 and 9.3 for comparison, 8.5 is perfect, 9.3 is jacked in the same way as 9.6.

So I'm sure it's a bug, *however*, the classic camera is only there for backwards compatibility and for the few things that the perspective cam doesn't cover yet. In other words, I'd bet that fixing it is a low, low priority on a fairly long list of things to do. Most of us use the perspective cam first and foremost, it is faster 95% of the time. The perspective cam with one of the new reconstruction filters essentially gives you the first few passes of aa for free, try it out.