Hi all

I am trying to create an soapy bubble Shader in Houdini, i need some advise how and were to start with.
any comments and advise will be helpfull

thanks!

If you want to physically model it, the phenomenon is called thin-film interference. There's tonnes of info and pseudocode if you google it.
These pdf's are pretty decent. The shading stuff is in part 2:

http://graphics.ucsd.edu/~iman/SoapBubbles/soap_bubbles_1.pdf [graphics.ucsd.edu]
http://graphics.ucsd.edu/~iman/SoapBubbles/soap_bubbles_2.pdf [graphics.ucsd.edu]

Be aware you have to calculate the interference for each frequency of light seperately. In the above pdf he chose to use 80 frequencies, which is massive overkill. It works just as well with 6, but just using R, G and B is not sufficient.

Please try posting an image that fits the average browser ………

A simple google search yields lots of information http://www.sidefx.com/index.php?option=com_content&task=view&id=1240&Itemid=305 [sidefx.com]

Rob

i had those PDFs and was quite useful. i was confused in implementing those values in the Shader level in Houdini..
so i am technically inbound as where to apply the information.

Here's a quick vopsop implementation. The ‘SPHERE’ is supposed to match fig. 17(b) from Glassners pdf. The wavelength-to-rgb ramp I've used is much better than whatever he used in the paper, which is why the colours are somewhat different.

also take a look at this thread http://forums.odforce.net/index.php?/topic/4788-coatings-iridescence/ [forums.odforce.net]

thanks alot! stabby.. thats really cool!!

and thanks Tomas!! )