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What is the best way to setup a material so you can control elements accurately in Cascade?


I need help on Particlerelativetime node.

I want to make a material where some properties change over the course of the life time of the material.

Can the Particlerelativetime node help? What does it do basically?

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asked Jul 23 '14 at 04:37 PM in Rendering

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avatar image Lovecraft_K ♦♦ STAFF Jul 23 '14 at 09:34 PM

Hey envenger -

The Particle nodes in the material editor are specifically programmed to work with a particular module in Cascade. For what you are wanting to do, a Time node would allow you to alter a material aspect based on game timer. You could also set up a float value and control that float value through a Blueprint Timeline control.

Can you be more specific as to what exactly you want to accomplish?

Thank You

Eric Ketchum

avatar image envenger Jul 24 '14 at 08:12 AM

Well there are 2 things I wish to create.

First the flipbook function in UE4 where there texture changes from the first image of the flipbook to the last over the life time of the particle.

I am using that material for my particles.

Considering here my particles have random lifespan, using the time node wont be accurate enough. So I came across the "Particlerelativetime" node.

Secondly I want to lerp between 2 textures over the lifetime of the particle. Using the time node here is not possible but the alpha over life time could get the job done. But i wanted to use something more specific.

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Hey envenger -

Ah, I understand completely and I have your solution...., Dynamic Parameters. Using this node will allow you to completely control how an effect is progressing through Cascade using either the life of a particle or the life of an emitter. It also just so happens that we have just posted a tutorial on there use, **here**.

Thank You, and let me know if you need me to explain further,

Eric Ketchum

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answered Jul 24 '14 at 06:45 PM

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Lovecraft_K ♦♦ STAFF
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avatar image envenger Jul 24 '14 at 10:13 PM

Ok thanks I will check it out.

I just wish to know what does the Particlerelativetime node do? Just for my knowledge.

avatar image Lovecraft_K ♦♦ STAFF Jul 25 '14 at 07:00 PM

Hey envenger -

The Particle Relative Time node returns the 0 to 1 calculation run by the particle system as it advances in its lifetime.

A good example would be to plug the Relative Time node into the Radial Gradient Expo. node as its Radius and the plug that into Emissive on a Additive/Unlit Material. Observe the effects in Cascade.

Thank You

Eric Ketchum

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