View Full Version : Rotoscoping QT's onto Flat planes ERRORS - help

10-28-2003, 08:38 AM
Hi All, I need some help figuring something out... I am having problems rotoscoping Quicktime movies onto flat planes and cutting them out with another Alpha Quicktime movie. I will get multiple things happening - the planes (I have three different movie sprites, each with a corresponding alpha) will default to one of the movies and disregard the others, including the alphas. I will also get a black window if I alter any of the texture attributes on any of these texture planes. They are each seperately UV mapped. I have also tryed to use TGA's sequences.

Or I get an error like this on rendering:

CKPT: Checkpoint block nesting overflow -- FATAL!

Any Ideas????

As for machine specs, I am running:

Lightwave 7.5
Dual 800 mhz G4
1.5 GB of RAM

Thanks in advance...

10-29-2003, 08:21 AM
Anybody? Someone must know a thing or two about this????

10-29-2003, 09:02 AM
I don't use QT in Lightwave, so I'm just grasping at straws to try and help you, but what if you converted you movies to image sequences? You mentined using TGA sequences, did you get the same result? If you have 3 (6 including alphas) different movies mapped as surfaces to three different planes, are your planes named differently (i.e. object 1 surface is named something like Movie1Surf, and object 2 is Movie2Surf)? Are you mapping the movies to the object as a texture, or are you projecting them from a light?

10-29-2003, 01:39 PM
Trevor, I had to read your post a few times to follow what you're trying to do. It seems like a surfacing problem.

The term "rotoscoping" usually refers to the manual task of tracing around an object that has no matte shape or alpha channel, and is usually done in a compositing app. I think you already have your matt/alphas prepared, but want to use them in Lightwave to create transparency.

Are you previewing your surfaces by pressing F9 to render a frame? This is the only accurate way to view transparency. Using OpenGL or Viper is not always accurate.

If you're just using flat "sprites", then UV mapping may be unnecessary. Maybe a simple planar projection will do.

In Modeler, did you select a different surface name for each object? I can't think of another reason why when you change the surface of one object, the other objects also change.

Solution: Try this.. Render your matte shape as a separate grey scale movie or image sequence. So then you've got two separate movies for each object... one is a 24-bit RGB, the other is an 8-bit gray scale matte shape.

In the Surface Editor, press T in the color channel, and add your color movie. Press "use this texture".

Then, in the Surface Editor, go to transparency and hit T again to add your gray scale matte shape.

Hit F9 to render a frame. I think it'll look better this time. The reason it didn't work before is because your Quicktime alpha channel was just cutting out one surface layer, but not affecting the transparency of the whole object. Two different things!

10-29-2003, 01:45 PM
Thanks for trying to help out, heres the breakdown...

I am currently using TGA sequences with the Alpha movie also as TGA's.

The Objects are all uniquely ID'd and mapped - ex. Ringmaster_bucket, Kids_Washing, etc

The Sequences are UV mapped to unique map co-ordinates for each surface.

Now one thing that is happening is when rendering "Selected Items Only" it will work well if the planes are the only things selected, but as soon as I render the scene, the movies are swapping out, with one becoming the dominant texture. This leads me to believe that it is a memory/texture allocation issue within LW... I have done this before, but this time seems to be particularly harrowing.... Any thoughts??

10-30-2003, 11:25 AM
ok....Heres what happened....
Opened the LWS file, hit F9..... at the point in the render where the Movie files were called up to render, there would be a sequence of error pop-ups - 1 for each movie file. GRRRRR.

Error message:
CKPT: Checkpoint block nesting overflow -- FATAL!

Here's the Solution:

1) Open the file, go into the "Surface Editor" window.

2) Select each of the surfaces with movies as textures, I am guessing to load them into LW's memory cache.

3) Render away!

This is definately a bug and I will be letting NewTek know for the sanity of future generations...

Thanks for all your attempts at solutions, It's good to help sort out the problem.

10-28-2004, 11:56 AM
I'm having the same problem. The "fix" worked for me too.

Lots of images mapped onto lots of planes with lots of alpha channels. I was getting that same error, but I selected a surface in the surface panel and held down the down arrow key to scroll through all the surfaces. Now I can render.

Apparently it still isn't fixed in 7.5d