Creating a blood trail in UDK

JamieRIOT

Hi,
I have been working on a UDK environment for a couple of months in my spare time now and the finish line is in sight, I'm just experimenting with decals and any final touches. The loose story of the scene is that there is a hospital room and corridor where someone/something has attacked the patient in the bed and dragged their bloodied body out of the scene. Here is some screenshots:








What I want to create is a continuous bloody trail from the bed, leading out into the corridor and out of the scene. I don't know what is the best way to go about, so would like some help/advice if possible. I have tried single decals (See screenshots above), but can't get the effect I want. See below for a disgusting quick mock-up of what I am aiming for:





Thanks in advance!
Jamie

imbueFX

Single decals could be a viable solution, it's probably a problem with the shape your texture in the decal that is the issue. (I only see your mockup, but I cant see a string of decals in any image above). But from what I understand, using lots of decals in succession like that is costly for performance.

If I were doing this, I'd model out a simple mesh that curves and bends as you see fit. The UVs would stay straight, however. You can then have one material the repeats a few times depending on the length. It's only a single draw call and much more scaleable that way.

Hope that helps!

LoTekK

I think you could get some good mileage out of decals, to be honest. Make a couple of splat decals, and a couple of streak decals, and apply as necessary. The multiple decal approach also gives you some flexibility to use in a gameplay setting, as opposed to being purpose-built for a specific scenario/layout (though that approach has its merits as well).

I think the main thing you're missing in the mockup above is streaks/smears. When you're dragging a wet object around, you don't just get splats and puddles as you've mocked up. You get lots of smearing. Maybe something like:



(from here: http://flickriver.com/photos/philly_police/sets/72157604289769322/)

Ace-Angel

I haven't used Decals alot, but couldn't you in theory have a BIG one in the area of interest, with detail maps to carry out most of the work, and maybe a vertex color for masking alongside a Direction Map to drive the smears?

It might get abit math heavy, but if you mutiple masks in mutiple channels, you get a wide variety of selection, enough to have it reused more then a dozen times.

JamieRIOT

@imbueFX - Thanks, that seems like a good method, but....
@LoTekK - ... This method seems a little more flexible. It is kind of like i have been doing, except my decal blood patches haven't been too good; I struggles with getting a decent alpha too.
@Ace-Angel - Cheers for the help. That method sounds a little too complicated for me at the moment. This is my first UDK level too.