i did some searching around and learned a lot but i need more info on these 2 -
1. sun direction - i see the sun controls in the lighting tab - direction & heading. but is there a visual gizmo somewhere where i can see the sun's direction? in the 3D preview or the small fractal window?
2. i want to render out a sky with clouds and would like to have an alpha channel so i can easily extract the clouds portion of the image. is there a way to enable this?
thanks in advance for the help!
cheers,
Rom
snowblindstudios.com
1. No way I know about.
2. No way I know about directly, though BigBen or Volker might know about something. Both of these guys have played a lot with masks and clouds.
You just need to get used to the Sun direction thing, I think. When you move the slider left the Sun moves left :)
For cloud alphas, and I'm assuming you have the Deep+Animation license, switch off the Atmosphere's Primary Rays, and render using the Sequence Output button in the Render options with the Alpha channel output option switched on. This will retain GI on the clouds from the atmosphere. Also switch off the terrain if applicable.
If you want to render an EXR, just change the .bmp extension to .exr by retyping in the filename extensions in the Render Sequence options.
:o
I didn't know you could do that.
Quote from: JimB on January 17, 2008, 11:43:56 AM
You just need to get used to the Sun direction thing, I think. When you move the slider left the Sun moves left :)
For cloud alphas, and I'm assuming you have the Deep+Animation license, switch off the Atmosphere's Primary Rays, and render using the Sequence Output button in the Render options with the Alpha channel output option switched on. This will retain GI on the clouds from the atmosphere. Also switch off the terrain if applicable.
If you want to render an EXR, just change the .bmp extension to .exr by retyping in the filename extensions in the Render Sequence options.
Neat trick about the alpha image, and I didn't know that about the file extension!
So,, uhhh, got any more little nuggets you care to share?
:D ;D
thanks for the info JimB!
does the Deep edition (no animation) have an alpha channel output option? currently its unlikely i'll get the animation edition.
cheers,
Rom
snowblindstudios.com
The alpha is automatically output to the TG2 temp folder upon completion of an image render. The Explore Temp Files option from the File menu should get you there, then select the most recent folder and image after your render completes.
A visual "gizmo" for sun positioning is among the UI enhancement we'll be considering in the future.
- Oshyan
TG2 automaticaly saves your alpha channels etc. in 'trmporary files'. You can find them by opening T2 and clicking 'file' >> 'explore temporary files'. You might want to periodicaly delete these files once in a while, they take up gig, upon gig of hard drive space.
I think that's what you want...
QuoteThe alpha is automatically output to the TG2 temp folder upon completion of an image render. The Explore Temp Files option from the File menu should get you there, then select the most recent folder and image after your render completes.
A visual "gizmo" for sun positioning is among the UI enhancement we'll be considering in the future.
- Oshyan
Beat me to it, man! ;)
thats brilliant! exactly what i need. thank you so much.
cheers,
Rom
What is this alpha image that gets output for (Or will before if the function required is still under development)? Aside from taking up room and slowing down the render process if they are generated at render time what do you do with them? ;D
Regards to you.
Cyber-Angel
Alpha images are basically masks....they are black and white and can be used to mask anything with that shape
Some links explaining alpha channels:
http://www.retouchpro.com/forums/archive/t-1567.html (http://www.retouchpro.com/forums/archive/t-1567.html)
http://nicolaescher.com/tutorials/alpha-channel-primer.php (http://nicolaescher.com/tutorials/alpha-channel-primer.php)
http://www.bertmonroy.com/tutorials/text/17_alpha.htm (http://www.bertmonroy.com/tutorials/text/17_alpha.htm)
They don't slow down the render process - generating the data used to create the alpha image is already necessary for the rest of rendering.
- Oshyan
I have the Deep / Animation version, but do not see the Alpha channel output option? Where do I find this? A picture might help.
Go to the Sequence/Output tab in your Render Options.
There are three fields:
Output image filename
Extra output images
Micro exporter
Extra output images is the alpha channel option.
When you render a sequence (for a single frame just render frame 0001 to 0001), you will have two images rendered. For example:
C:/temp.%04d.bmp (this is the red, green, blue channels)
C:/temp.IMAGETYPE.%04d.bmp (this is the alpha channel)
If you did the above and looked in your C: directory after rendering, you'll find the following two files:
temp.0001.bmp
temp.alpha.0001.bmp
Thanks, Jim. Understanding the names and how things works is a great assistance. Thanks.
Everything is in working order. 8)
Probably a stupid question, but what's the alpha channel? The sky?
The Alpha Channel is a greyscale image that defines transparency, used for compositing different images together in apps such as Photoshop, Shake, After Effects, etc. Basically, a greyscale image mask, just like you would use for an image based blending shader (white is solid, black is transparent, grey is semi-transparent).
If you do a normal render, with surfaces and atmosphere switched on, etc, you'll find the terrain and clouds are solid white, but the sky will graduate from solid white at the horizon to grey at the top. I assume this is because the sky has a depth, it gets thinner with altitude but there is only empty space beyond the sky (therefore nothing to render beyond the sky).
If you switch off atmosphere completely in your render options, you will find the terrain solid white, but the sky will be solid black in the Alpha Channel rendered frame.
If you go to your atmosphere options (where you add clouds, etc) and switch off Enable Primary for the actual atmosphere node itself, then the terrain and clouds will be solid white, but the sky itself will be solid black.
NB: When I say the clouds will be solid white, I mean they will be grey at the edges according to the transparency of the clouds.
Make any sense?
I know what an alpha channel is ;D I asked what THE alpha channel is, not what AN alpha channel is ;D haha....next time I'll be more clear in asking :)
But thanks for your explanation and yes it makes sense :)
Thanks for explaining, Jim.
Awesome! That's a feature I didn't even know I wanted! Thanks for the heads up Jim!