In this video, I’m going to give you a short
example of the UV offset map drawing mode in Krita. This video is here to give you an
example of what you would use flow maps for in practice.
This is not a blender tutorial and this is not a technical tutorial on how flow maps
work for shader programming for instance. For the most part it is for those of you who
do some technical Art. It is used mainly in real-time rendering with shaders. Working
with this tool is very straightforward. You just have to select the 2nd preset in the
tangent normal brush engine in Krita, and then you just draw in a given direction to
create vectors pointing in that direction. Just like with tangent space normal map the
color 128, 128 and 0 to 250, whatever… is a base color that represents a neutral vector.
I prefer to fill the blue channel with a value of zero just so that I can at a glance differentiate
my flow maps from my tangent space normal maps.
Krita’s convention for mapping the colors is the opposite from some of the more popular
engines out there. That is unity… I noticed that it’s the opposite of blender as well.
You will either need to invert the R and G channels in your engine upon importing the
texture, or you have to do that in Krita. You just have to press control I to invert
or you can add an invert filter layer on top of your layer stack to do so.
Once you have exported your texture you can test it out in a small application called
flow map painter. It’s a unity maze application with a flow map shader built in, which will
give you a preview of the kind of flow your flow map produce. To use it you just have
to rename your texture flowmap.PNG, and place it into the data folder of the little application.
Then, from within the app, you can load your flow map by clicking the corresponding button.
I also prepared a blender note setup. It’s not working perfectly. There’s definitely
something that I’m missing out there, but I didn’t have the time to fix it. if you
know how to fix the global of said that’s happening on my setup, don’t hesitate to
share the solution in the comments! The setup itself is simple. We connect the object’s
UV coordinates to a mapping node to be able to pan and scale the texture. To that, we
add our process flow map. It is our texture to which we subtract 0.5 to get both negative
and positive coordinates in our vectors. We then input our results in the vector slot
of the diffuse texture. This slot handles UV mapping for the texture image.
That’s about as far as I can help you with flow maps and Blender right now. I’m really
not a crack with Blender so if you want to use flow maps, you’ll have to do your own
research. I couldn’t find a tutorial either to run me or run you through the process of
using flow maps in blender specifically. I hope this tutorial was still useful. That
said, I want to thank you all for watching. See you in the next video!