Vector Fields from 2d image file

[RyanGadz]

I’ve been reading though the docs and found something interesting about vector fields for the movement of particles:

Additionally, vector fields may be reconstructed from a 2D image. In this case, an image much like a normal map can be imported and used to reconstruct a volume texture by extruding or revolving it around a volume. A static vector field may be added on top of this reconstruction to introduce some noise and randomness. Further, the 2D images may be animated by storing individual frames in an atlas texture. Doing so allows you to perform a fluid simulation offline and reconstruct the motion in real-time at very little cost.

This is exactly what I have been looking for but I have not been able to find out more about it. How does one create these image files, what do they look like (assuming something similar to normal map), and what file format are they?

[DieByZer0]

No info on it yet, It isn’t introduced i guess by their Particles department. Good question though lets get some more info by Epic on this one.

[DieByZer0]

A quick Trial and Error i did as i am also new to the fluid mapping in UE proved my theory correct, Seems like you can capture a 2d texture (fluid map) from Maya and import that, The map looks like any noise map (pretty similar look to the PS render clouds).

I will wait for someone from Epic to confirm and put the whole process in the Docs.

[Sam_Deiter]

@RyanGadz;2397

I’ve been reading though the docs and found something interesting about vector fields for the movement of particles:

This is exactly what I have been looking for but I have not been able to find out more about it. How does one create these image files, what do they look like (assuming something similar to normal map), and what file format are they?

You need to use the Maya shelf tools which you can get from the following location.

C:\UE4\Engine\Extras\FX_tools\Maya2012_x64

Once installed you can then use this tool to generate vector fields based off particle data you generate inside of Maya. The tools allow you to export the data from Maya and then import it into UE4. Once imported you can just place in the world to see if affect your particles. Also you need to make sure that your particles have the vector field module in them in order for this to work.

[DieByZer0]

@Samsterdam, He isn’t talking about the actual container. That process is pretty clear.

[RyanGadz]

@Samsterdam;2786

Once installed you can then use this tool to generate vector fields based off particle data you generate inside of Maya.

I was looking for a way to make them in Maya before I read the Unreal docs, now I am more interested in generating them from an image file that I could make in Photoshop for example (although I thank you for the Maya tools and will be trying them out).

I imagine it would be a very similar approach to creating terrain from a heightmap.

something like that

[RyanGadz]

@DieByZer0;2767

A quick Trial and Error i did as i am also new to the fluid mapping in UE proved my theory correct, Seems like you can capture a 2d texture (fluid map) from Maya and import that, The map looks like any noise map (pretty similar look to the PS render clouds).

is it a special file from Maya?

[DieByZer0]

I am not a maya user, I tried with photoshop by inserting a Noise map and it works, In Maya i think you need a 2d container and to render that texture out from maya fluids let me know if you can’t figure it out and i will install my maya for it.

[RyanGadz]

@DieByZer0;3039

I tried with photoshop by inserting a Noise map and it works,

Perfect! That is exactly what I wanted to know

[DieByZer0]

Do note that this isn’t accurate at all because the “render clouds” or generally the creation of noise isn’t accurate and can’t be controlled, Thus extracting fluid 2d maps from Maya is the right way to go but as a place holder you can always use a noise map.

[Rhayader]

Maybe it’s a late reply, but Epic has a tutorial on flow maps painted in Photoshop here: Photoshop Generated Flow Maps - Unreal Engine

Still trying to figure out if I can make a flow map in Maya using Bifrost, e.g. making a river and exporting the flow map from there. Because Bifrost is awesome with liquid simulations. Alex Vlachos talked about generating and using flow maps in Portal 2 in his GDC talks. Here are the slides:

http://www.valvesoftware.com/publications/2010/siggraph2010_vlachos_waterflow.pdf

http://www.valvesoftware.com/publications/2011/gdc_2011_grimes_nonstandard_textures.pdf