How does it differs form one another?

I have been looking everywhere and thought these could be interesting to know.
Well i am no expert but it is incredible how much channels can these OpenEXR handle.

I do know for VFX is more common the use of OpenEXR but i was reading that the IMG outputs 48bit so what is the deal here, the other 16 bits are one for z-depth and another for. ?

Is all confusing to me, i hope somebody can clarify these to me or provide me with some link i just give up looking for answers.

PS: Nuke can read all those OpenEXR channels in the image i havent had the chance to try it with an IMG file.How will you do this just save it to an RPF ,but than your GI channel information will be lost.

Gracias

Hi, Edgard

1. OpenEXR can store data in different formats but in real practice “HALF” sub-format is fully dominated. It’s 16-bits per channel, that, however, is treated as floating point number. In other words, .exr file is a hi-dynamic range image.  Data storage - 16, data usage - 32

2. EXR can have very different channels, customs as well. Unlike .hdr, .exr can have alpha channel. EXR reader can convert other channels into standard RGB. But for saving miscellaneous info (like layers) .exr is not very suitable because saved custom info has no chances to be “understood” by 2D apps. If “just 32-bits” output is needed - so you can use “not-clamped color” RPF channel.

I am just thought you could bring a render from EI and the that render containing all your different channels, diffuse,spec,reflectivity,i asuppoased this could be done via RPF but what about the GI channel in this case you could add an APass to bring the GI channel?
I can tell these is very simple to use but yet is so much handy.

PS: Ias there an issue with Transparencies that i am not aware of? I know i must be forgetting something is being long time since i start using EI
When rendering glass everything works correctly except when you display the alpha channel of your render is all matte out. Like is not reading the transparencies in the alpha.You could put an object behind and it will refract but when displaying the alpha is all white out.

Well i am understanding a lot more , thanks Igors

Edgard

Hi Edgard,

You’ll need to watch the movie called “Alphas for Raytrace transparency” on the tutorials page here.

Hope that clarifies it,
Ian

the movie doesn’t work i have tried yesterday for the alpha transparencies

Can you upload a screenshot of your work? Are you using RT transparency?

The movie itself does not work? Or you can’t get the technique to work?

Ian

Yeah is RT transparencies with a RT light , once you put any object behind it AShows the refraction but not on the alpha no problem just wanted to know how to in case i need to composite with another image. here it is.  Probably is because i am only using the demo at this time havent got paid yet.

PS : Is it possible that the problem is on my material or is a rendering issue?Or perhaps isa my material setup?Or probably asometing in the light i am missing here?

Back to track.
WHen i read that IMG producesa a 48bit image i was amzed. SAO i want to know if they are talking about 48 bit per channel?
Since i want to render out a separate channel.
Can i do thesae through RPF or saving as IMG and converting them to .exr will do it?

The reason you are not getting the alpha mask you expect has to do with the way RT transparancies work.  If you phong render the transparency, you may get a closer result.  I think that’s what Ian is suggesting, and a more elaborate explaination (AKA workaround) is here…

http://www.eitechnologygroup.com/forums/viewthread/278/

Yon

PS nice lighting and reflections on the glass.

thanks for the tip Yon, i guess i will bring my background animation into animator so i can get the background image to refract.The headache will come when i need to composite in a live action plate there fore i will need to apply this technique described by Ian. But the alpha shows an alpha with no refraction caused by the glass properties.

Thanks for the comments i could have used a caustic it looks very nice with caustics if i had the real version i could work more in it but it is only the demo version. well i guess i have to wait a bit more.
Those are the things why i rather use another software with les headaches but i was doing some tests render with C4D and EI. And as soon as you increase the sampling in C4D it takes a few minutes to render less than on EI. But when you activate the caustic option on the light and on the renderer . I could be there forever, just waiting for one single image at 720 by 576. Well i am on a MacBook Pro 2.16 1gb ram that is probably why.These image i rendered out at Anti alias 8x8 Sampling level 2x2 and the speed was very amazing Camera is very good. The materials are good in some areas i wish it could be more interactive like a box set on your view where you can control the positioning and a better preview will be also incredibly useful.Texturing and lightning is a part that i enjoy the most from 3d.The lightning in Animator hard to master but if you have to do a test render every time you modify a light setup you could die waiting there.
I guess people that are lightning specialist just have a setup for every possible scene.

For example i am using shake and i want to bring my render directly form EI and i want to be able to render a movie as .EXR? Than what should i do?  That is the initial question. Should go through After Effects convert the movie into an .EXR? Or can EI render directly to .EXR?

Thanks , i hope i express my self clearly.

Test renders needn’t take much time, there are many, many little tricks to speeding up glass rendering. Firstly turn of Anti-Aliasing for all your test renders (you will see a 10x speed increase in some cases). Also turn off ‘receive shadows’ for the glass too in the group info window.

The HyperGlass video tutorial I did for Paralumino goes into this in more detail.
David has done some great videos on lighting also available from Paralumino.

The current release version of EIAS can’t render to .exr,
Ian

Thanks for clarifying and for the tips as well.