Help: Fake Transparency for Cloak Mode

[FTC]

Hi,

basically I want to create a material effect like the cloak mode in crysis. I already tried the different transparency options for the material, but none worked out like i would like them to: I can either disable shading completely, or I have to live with the fact that faces are visible, that should not be:


I want it to look like this:

(not an actual screenshot - edited with gimp)

I figured out I need the scenetexture for this, but it only works with transparent materials. What I would do is: First render the scene without the cloaked object, then render the cloaked object with a solid material but textured with the scenetexture to make it seem transparent. Dependant on the percentage of cloaking I would blend between the scenetexture and another solid texture.

The question is: Is this possible? If so, how is it possible?

greetings

[Hellclown]

UT3 had a cloaking power up, so it is possible.

[FTC]

Thanks, by searching for UT3 instead of UDK I have found a few pictures/videos about the Nightshade's cloak and about cave crystals that look somewhat like what I want, but no hints whatsoever on how it is done

greetings

[geodav]

first try having a look at the UT3 code which is available on the udn site, if its a material then spend $10 for UT3 and have a look at how they did it

[FTC]

It is a material (VH_Nightshade.Materials.M_VH_NightShade_Skin). However there are two counter arguments: first I am not exactly sure if the material actually does what I think it does (all transparent materials from the udk or the ut3 demo do not) and second every online shop I checked so far said it wasn't available in my country so that is a bad omen I will still look it up at the local store tomorrow.

greetings

[Xendance]

I think the material has to be switched in the game code to the translucent one.
FYI, here is what I came up with regarding the cloak material.

[FTC]

That looks pretty perfect
Yea I think switching Materials is a necessity. After playing around with the settings it is possible to blend from cloak to almost solid, but not entirely.
Still I will try to get ut3, seems to be a good idea- and sample-repository.

greetings

[Hellclown]

Xendance, what texture are you using for the distortion?

[FTC]

I got it working!

The idea is quite simple actually: Change the Blend to Alpha Composite. Then for a solid appearance set the diffuse to whatever it should be for solid. To have the material appear transparent plug the DestColor into Emissive and use the Distortion. The Cloaking-Effect is done by simply multiplying the two material 'types' with a factor:


By lowering the opacity parameter over time the cloak activates:


Not a final material, though, but I never thought I get this proof of concept done so quickly. Thanks alot to everyone!

greetings

[Hellclown]

Is the blend triggered in code, or does it just happen in a loop during gameplay?

[FTC]

Right now the Cloak is not dynamic. I have created a MaterialInstanceConstant and can set the 'Opacity'-parameter to the desired value. Wether I will use this in a Script or within a Cutscene I can controll the cloak with that parameter. I am doing neither, yet, but I will go for the scripting method eventually.

greetings

[Niteshade]

Interesting thread.
Could someone upload the material +textures in an UDK package so I can have a look? I'm not very good with the node editor yet.

[FTC]

Here you go:
http://freetimestudio.homeip.net/Cloak.upk
The textures are from the default content of the UDK, but you can use any diffuse or normal texture you want.
I also included three sample instances:


greetings

[Niteshade]

Thanks a bunch

[shuriken88]

Wow thanks for the knowledge and meterials here, Predator would be proud!

@Niteshade

Which book is that quote from? I've only read F&L in Las Vegas, but it was one of the best books I've ever read, or more, "experienced". Same goes for Clockwork Orange and Trainspotting.

[siegf]

Hi, I know it's a old post, but i couldn't find the package and was trying to reproduce that, the problem is that even if i plug my texture into diffuse for the opaque version. With Alpha_composite i can't get anything fully opaque.

[FTC]

Hi,

it should work with BLEND_AlphaComposite, because this mode allows using no alpha at all but still have SceneTexture and depth functions available.
Anyway, I still have the package and reuploaded it:
http://www.freetimestudio.de/misc/pr.../udk/Cloak.upk

However a fully opaque AlphaComposite still has no shadow and a very poor shading. You should create a Solid material that looks very familiar to the opaque cloak and switch materials when the cloak is activated or deactivated via script.

greetings

[siegf]

Thanks FTC! Will check it out, yes i was thinking about switching anyway, but the opaque with alphaComposite was transparent, and I got no idea why. Will try it now, thank you.

[siegf]

Ok I found out something really odd. Your shaders is transparent on my mesh too. So i tried it on another mesh and it works. Even the shader I had before works too. My question is, what could cause a mesh to be transparent and another not while they share the same shader?

[FTC]

Does your mesh have any vertex colors? It might have to do something with that, however the shader does not use Vertex Colors, so it should not affect the transparency.
Then again I am hardly a professional at shaders.

greetings

[elvince]

Does someone have the sample package available? I want to look at it and share it with my team for learning purpose on this

Thanks,

[Kelt'ar]

Look for radioactive infestation on google code...it should help/

[elvince]

Thanks, I found the code & the upk.
I need to test it and look into it but I have a starting point