View Full Version : concatination...???

11 November 2004, 12:16 PM
I had a shake class the other day that left me a little confused. Just what is concatination exactly????

11 November 2004, 08:37 PM
Concatenation is when you put a load of nodes together and they actually all act (internally) as one node - this means that the processing is a lot quicker...

A lot of transform nodes can concatenate (the ones with the C in the corner), and so can a lot of colour nodes...

11 November 2004, 11:03 PM
just to expand on hugh's response. concatenation is a very essential part of film and high bit depth compositing. It is not enough just to lay a bunch of nodes together and call it a comp. to use a program like shake properly takes a fair bit of skill and understanding. concatenation is a process which combines multiple opereations liek colour corrections or image transforms and applies them as A SINGLE OPERATION.... this means that it is faster more accurate and results in less data loss

Have a read in the doc's about what to do and what not to in terms of preserving data quality but here is a quick quote

if you have ten concatenating Color operations in a row, it internally compiles them into one big lookup table, and executes it (internally, one node is processed, rather than ten). An important second benefit is that by not clipping your data, you preserve much more mathematical information. Therefore, concatenation preserves quality and speeds up your processing time. This is good.
breaking concatination but putting a non "C" concatenating node inbetween multiple "C" nodes is BAD unless absolutely necessary.

11 November 2004, 09:13 AM
One thing that came up on the Shake mailing list recently is the point that Bytes nodes also concatenate (Try a ColorWheel at float, followed by a brightness set to 3 - the center values will be getting on for 3 - add a Bytes set to 8-bit - the center values are clamped back to 1 - follow this with a Bytes node set to float - the center values are back up at 3 again)

11 November 2004, 11:07 PM
ok! now I sort of get it... thank you! I am always amazed at people who take the time to answer my questions . I would too if I knew more answers... anyway thanks. I have this teacher in shake ( manuel gonzales) who is nice and seems to know a lot but sometimes he just sort of takes for granted that everybody knows things that well at least I dont. He seems to think we are all photoshop and compositing veterans just learning a new software and I guess some people in class are but not me. Like he says well how do you guys think we should do a bleachpass in shake? Like I ever heard that word. he must hate me cause Im the only one allways asking well but what is that? again: anyway, thanks a lot

11 November 2004, 09:07 AM
I certainly appreciate the help I got when I was starting out (only a year ago, to be honest...) - I was working as a runner, but spending my lunch breaks and evenings sitting with the compers on a spare machine - they were very happy to answer any questions I had about Shake.... (I remember getting a little confused about Concatenation myself...)

11 November 2004, 06:00 AM
I am glad to be of any assistance.

I know it can be intimidating to put yoursefl out there. I beleive that one should never be afraid to questions. I am no uber-veteran with all the answers, I beleive it is best to speak up when some asks something I know because people will generally return the favour and as a result everyone's knowledge gets better. I hope the class goes better.

I still have lots to learn and always appriciate a chance to learn something new or different.

Good luck

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