Friday, June 14, 2013

Here is a creature concept I have been working on for some night the past two weeks. I call it Osedax (which means sea worm in Latin apparently)! 

Tuesday, April 30, 2013

Join the Mari Forum!

Just a quick update to inform people about this forum. It is a really great forum, but it needs more people with a voice. So go join it so we can get some Mari discussions/problem solving going. -

Sunday, April 28, 2013

Here is the trailer for Man of Steel. I helped with texturing and modeling work on one of the spaceships.

How to properly combine displacement maps

Okay say you have an asset that takes up multiple UDIM tiles like the one pictured below. This happens 99.99 % of the time when you are in film production. Even simple props like swords, shields, a horse in the bg, etc. most of the time have multiple UDIM tiles laid out. 

Now imagine this model having multiple displacement maps for each tile. It is often required by the lookdev/lighting department to have multiple displacement maps for a character. That often comes down to low frequency, mid freq and high freq. And sometimes they even want a displacement map for a specific area.

So that's why in Zbrush you should always sculpt low, mid and high separately when working in production. At least for hero/mid ground assets. There is nothing worse than having them all sculpted into one map/layer and then suddenly lookdev asks you to separate out the high from the low so they can have more control in the shader. 

So to avoid problems like that, you want to sculpt your displacement maps separately. I usually have a layer in Zbrush (or mudbox) for low, mid and high. Now when it comes to exporting those maps you should export them separately (unless you know for sure only one disp map is required). There is a nice Zbrush script for this below. It is written by my friend and colleague at MPC Jake Harrell.

So here is an example of what you might have. This is some displacement maps for an iris/eyeball.

Ok now it has come to the point where you have to hand over your maps to guys in lookdev. But lets say that lookdev has only requested one map where all the information is in. to save to render time.

Okay time to combine these maps! But how do you do it properly? Yeah you can open Photoshop, open your 3 files, change the values, add them together, save out 32bit 8k map and then wait for the next 5 minutes while it saves it out, and then do them same thing again for the next UDIM tile. A bit slow and time consuming no?

Instead lets fire up NUKE and do it there! 

So load in in your file you want to combine. Now lets take a look at how a displacement map usually looks like in the graph below. The blue dot represents your displacement map on a linear scale. That is usually where your information is depending on the strength/scale of your map.
Now to combine a displacement map the correct way you want to ''add'' them together. (called ''Plus'' in nuke). But from our graph below we can see if we add 0.5 and 0.5 together it will equal 1 in value? Therefor exploding your mesh at render time.  

So what you want to do first before adding the images together is to change the values to something the picture below. To do that add in an ''Add'' node under each image file. Change the value for each one to -0.5. Now your disp maps becomes black. And if you hold down CTRL while pressing your mouse over the image in NUKE you can see the values have changed. You will probably have some minus values as well in there. And that is exactly what you want. So now the blue dot is both in plus and minus. 

Now you want to merge them all together, so select all the add nodes and hit ''M'', now change the operation to ''Plus''. Now we want to change the values back, so that 0.5 is mid instead of 0.0. So select the merge node and add in another ''Add'' node and the value on that one to 0.5.

That's it!

Here is my node graph of the final composite

And the final displacement map. (... and yes the noise is way too strong)

Now you might be thinking that would be faster to do in photoshop, but imagine you have a huge asset. Maybe something like the spaceship from Prometheus, with 100's of UDIM tiles and they want a tiny little extra noise in the displacement map. Good luck with doing that in photoshop.
That's why if you name your texture files with the UDIM number at the end, you can load them in as sequences in nuke and work in multiple textures files at once. so in this case mine are named ''name_udim.exr''

Thats it! If you have any question or feedback let me know!

- Klaus

Saturday, November 10, 2012

Here is the trailer for WWZ that I was lucky enough to work on while at was at Cinesite. 
I also helped out doing 3d set design for Paramount Pictures for a short while.