can you achieve transparency in 3D environment?
Mar 26 2010 | 2:47 pm
hello, i am a first year digital media student and have just introduced myself to max/MSP. i am working on project right now for my uni assignment and i am trying to create chromakeyed plane in 3D space with 3D cubes spinning around it. i have tried so many things and still it doesn't work as needed and i really need some help and professional advice.
aim::
achieve this sort of effect in max/MSP
http://www.vimeo.com/9757459
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+ use live green screen video feed
+chromakey it
+import it in scene with 3D elements around it
+track the movement of person from live feed and apply these values to trigger 3D elements.
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i managed to apply live feed onto a plane as a live texture and import it in 3D space along with the cubes
i also managed to sort out tracking and applying in on movement of 3D cubes
every time i was doing chromakeying the keyed areas appeared as black on my 3D plane. i have to get rid of those black areas and make them transparent. i don't know how to achieve that!
the only problem i am facing is getting my videoplane transparent in 3-d space.
i have explained the process and supported it with patches i was working on in my blog here:
http://kavi9999.wordpress.com
i am very confused and apparently there isn't a teacher in my department who can help me to sort my problem. i have read many forums and tutorials, maybe i am looking in wrong direction, please open my eyes!
--i need to know how to achieve transparency on 3-d plane and apply transparency on green areas.
thanks,
kavi
- Mar 26 2010 | 2:54 pmhere is screenshot of one of the patches i was working on:
- Mar 26 2010 | 2:56 pmi might be doing wrong thing by chromakeying it, all i want to achieve is just body appearing in that plane without black areas which are keyed. cheers!
- Mar 26 2010 | 6:58 pmwell, sounds like you have two problems to sort out.the first is to enable alpha based transparency on a textured 3d gl object. this can be achieved by first ensuring that you are actually sending a matrix with a proper alpha channel to your videoplane, and then setting @blend_enable 1 and @depth_enable 0 on your videoplane.the second, more difficult problem, results from the fact that you need to turn off depth_enable in order to properly display transparency. therefore you can't rely on automatic depth sorting and you have to handle it yourself.one way to do this is with gl objects @layer attribute. here is a very simplistic example, but should get you started. you use the z value of the circling gl object to change it's layer attribute. this assumes the videoplane is at a z value of 0, and that the camera is in it's default position and default lookat.you could encapsulate the circling object code in a poly~ and have several of these going simultaneously.
- Mar 26 2010 | 7:36 pmhi, robtherich!!! thank You for replying and directions, i will get straight on this one, thanks a million! /
- Mar 26 2010 | 8:50 pmIT WORKS!! thanks to your explanation and example patch i am nearly there, bit more tweaking and i should be sorted. i will post my final crit results here, thank you soo much, i do appreciate your help>>>>/
