Combustion display help

#1

OK. I’m a newbie learning Combustion. I have the book “Combustion Ground Rules” and am going through video tutorials. Have a problem with chapter 3 regarding masking between two layers. I have two layers. The top layer I add a “Draw mask”, draw a box, set to “invert” and then set first image as “background”. When I set first image to background I get lines across screen. I’ve rebooted, updated my graphics card drivers (Nvidia geforce fx 5500). Also tried using image files from cd on hard drive - didn’t help though. What am I doing wrong? I’m using Combustion 3.0.0.161.

#2

wait a sec, you are selecting the top layer to be the background ?

also, what are your Open GL settings ?

#3

No, there’s two images. A city vista and a sky background. The tutorials wants the user to put a mask over sky so that background of sky will show through.
Where do I go to change OpenGL settings? I’ve turned them on and off using file/preferances but with no luck.

#4

yes, they are set in file/preferences. you can also toggle ‘use opengl’ in the “window” menu.

you may want to turn off ‘use texture memory’ in the preferences. also, what videocard are you using ? do you have the latest drivers ?

#5

I think that it is definitly a open gl problem.

Try the software renderer in the composite settings.
I would suggest you to turn on “software open gl” in the preferences.
The only operator where you really need opem gl are the particles.
With your card there won´t be much hardware acceleration noticeable.
Open gl in combustion is alike two sided sword.
It helps you for creating simple motion graphics layer in realtime and orbit around your comp (just need that when doing 3d compositing), but with real footage
it could be annoying.
for example open gl has various display limitations. btw that is not (discreet) fault.
Transfer modes like negative or difference are not supported under open gl.
I think only add and screen will function properly.
And again open gl is limited to 8bit.
So my advice: buy a workstation card like nvidia quadro fx or work with the software renderer. Most of the time the final render is done with software rendering, too.
So if want to work with the final look while working switch to software render.

p.s. I had a similiar display problem with a matrox parhelia card

#6

How to a change to use software renderer rather than opengl? Would simply turning off opengl in preferences do this? I tried switching it on and off with no luck.

#7

Ok there are three Open GL settings that could be on - sounds complicated?

  1. Turn on “Use Software Open GL” in the preferences.
  2. Go to your composite settings and switch from Open GL to software.
  3. Right click in your composite viewport and make sure that “use Open GL” is not selected.

I try to explain why there are three settings.

The 1. one is a global switch. Here you decide if combustion make use of hardware or software Open GL if you switch to it by 2. or 3.

The 2. one is only used if you plan to do the final render of your composite with open gl.
The 3. one is used to toggle Open Gl temporaly on - just for orbit around in the perspective or painting.

So I think the most common way is to toggle it like in 3.

If you still have display problems while completly in software mode (1.2.3.)
then it could help to install another nvidia driver.

You could also use “rivatuner” to patch your geforce to a Quadro Card, but that is NOT legal.
So if you do so do it for testing purposes only.

#8

Just found simple solution. Tried opening file on another computer and had no problem at all. Must me graphics card like you mentioned.

#9

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