View Full Version : Vue xstream sync and GI problem
05-05-2007, 02:54 AM
I'm new here and was hoping if someone could help me out..
I'm making a short movie (combining live action with 3d) using maya7 and vue xstream 6. I've tracked all my shots and converted the data intdo different maya camera's. For the background scenery I use vue and maya does the rest. I've tried to render my scenes through the vue camera in mental ray and everything seems to work well... But when I try to render my scene with the maya camera it only shows the objects made in maya itself. I guess this is standard but how do I get my vue camera to behave like my tracked camera? With exact the same focus distance etc.. This is important otherwise it will not match the live action elements. I've searched the vue manual but couldn't find anything.
I also have a problem with GI and caustics. Rendering my objects without the vue file (only my maya objects) gives a good result but combined with vue it results in a flat, blue image. I thought it could be the GI setting in vue but that didn't make any difference.
I hope someone can help me out... Thanks!
05-06-2007, 09:15 AM
To make the Vue camera behave like your Maya one, I would copy the Maya settings down and apply them to the Vue cam, in the Vue interface, object manager, with the camera selected. The only problem might be that the Vue camera may not have as many options as the Maya one, bit I don't know Maya, so this is all I can say.
It would be good to know wich Vue atmosphere you are using, because the blue could indeed be caused by Vue. Check the atmosphere editor in Vue, and look for the "light" tab. Check how much skydome lighing gain you have, and if there is some lighting gain ( there is in most GI atmos), change the overall sky colour to a much lighter blue. This colour is used to define shadow colours. Also check how much ambient light is used in the scene. You may need to move the ambient/sunlight proportion slider to 60% towards the sun. It will give more contrast to the render, and tone down the overall blue tint you have.
Also a screengrab would help.
05-06-2007, 03:07 PM
Thanks for your reply Bruno,
my skydome lightning gain is set to 0,3 with a slight blue color assigned to it. I've used the basic sunset preset as a base and added some clouds (cumulus, cmulus layers and altro stratus). My ligt balance is set to 60 a s you mentioned. A light fog has been added with the intensity set to 50% at a altitude of 5m. I played a lot with the sky decay amount to get the right light balance. After a couple of tries a better result came up. Light intensity is set to1.5
I've made three renders so you can see:
1: no GI (http://www.enve.nl/coen/10.jpg)
2: no GI close (http://www.enve.nl/coen/13.jpg)
3: GI (http://www.enve.nl/coen/15.jpg)
Overall I think the GI render has to much blue in it. What has to be done to give it the more yellow, orange sunset look with a higher contrast and overaal darker image?
As for the camera I was able to insert my tracked camera details into the vue cam but am still not able to have it rotate and move like my tracked maya cam. Tried to parent it, used constrains etc. but I guess vue uses different coordinates and therefore has some script for it's vue cam to behave normal in maya. How can I get vue to recognize my maya cam? Or get the vue cam to behave like my maya cam?
05-06-2007, 10:48 PM
From your renders, it seems you are using a standard atmo ( non spectral), so I would do this:
Change the overall sky colour from light blue to something brownish.
Notice that ambient and light from sky colours will change, you'll need to reassign a blue colour to the ambient lighting, and maybe some orange tinted colour to the light from sky.
Decay of sunlight colour can also change dramatically the overall ambiance, in your case, play with the decay rate, the less % the more orange you'll see over the scene.
Fog and haze colours also have an important role in the overall ambiance.
Now if I'm wrong and you are using a spectral atmo, settings will be different.
About the camera, there is an updated camera synch plug in available over at e-on ( software update page), so you can import your Vue cam in Maya, but I don't know how it will behave with the Vue scene loaded in Maya.
Sorry I can't help more about xStream specific questions, I know Infinite very well, but I'm learning xStream right now with the PLE, and for a different app.
PS: what base atmosphere do you use? It's strange that just turning GI on leads to such dramatic colour changes.
05-07-2007, 02:00 PM
Thanks again Bruno,
I've been playing around with the atmosphere settings and have been getting better results. I was using a spectral model (basic atmosphere) with some clouds added to that. The azimuth and pitch were slightly off so I corrected them. The ambient light settings were initially set to a somewhat pink colour. Turned these into a light blue (as you said) and switched the light from sky to a more orange colour. This seemed to work. I guess all these different parameters are involved with the GI output?
I solved the problem with the camera. I had to make some changes in the hypershade concerning the vue nodes connected to the camera. Thank god for that!
I've put a quick render online for you to see. If you got some commends on the vue atmosphere please let me know. I'm pretty new to the program and althrough it works fast it has some nasty twists you have to learn. Finally I can go and complete the scene :) Greets!
05-08-2007, 12:49 AM
Looks good now!
One of the most important parameters in the atmo settings is the overall sky colour, it's the colour that is added to shadows, for example with GI lighting. This colour is the average colour that results of many parameters such as the sky gradient, sun azimuth, and ambient light. If you change any of these parameters, check your overall sky colour, because chances are the colour changed.
Also if you use radiosity, this colour is the main colour that will be bounced of objects in your scene, toned by the colour of your objects, unless you check "indirect sky lighting" for more accurate (but slower) results.
05-08-2007, 12:49 AM
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