Growing Roots with WPO

This week we have a look at how to use World Position Offset in our shader to create a growing roots effect.
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[@BucketKingu]

Not only did you show how to make the material and effect, you also showed how to make the mesh. Absolutely amazing detail man, excellent as always.

[@themeskimoze]

man i cant get enough of your content truly one of my best resources for learning about VFX

[@AllesLatte]

super nice! thanks for sharing the knowledge. im wondering if that technique could be applied to a spline mesh, so you could even generate the mesh in-engine and maybe even modify on runtime. definitely gonna check that out!

[@tharlevfx]

Yup. All those things are possible with this technique

[@TOMAvatars]

Hi! Thank you very much for your great content. It always helps me. But I don't understand something here: when I use negative values multiplied by the Vertex Normal WS it doesn't shrink, it grows.

[@CKostopoulos]

This is awesome, thank you a million times!

[@doomstarrobo7807]

This is very very cool. Thanks for sharing.

[@tssirivantalu4188]

Thanks. We need more

[@CaptainWeirdBeard1]

Thanks so much!

[@fragelius]

aaa yiiis ty for tutorial

[@srknAyn]

thanks

[@ImaginaryCreation-jm4xf]

9:08

[@javideas]

If I understood correctly, you are masking-unmasking the mesh, but the mesh is there the whole time in a fixated shape and position, is that correct? So if we want to not "reveal the trick", we should stop the player to step on the invisible but existing mesh. How is this "displacement" (when you change the width of the Roots) affects Collision? Also, the "column" where these Roots are growing cant be moved (if, again, we dont want to "reveal the trick"), right? Thanks

[@tharlevfx]

Correct - it’s all fake. Collision isn’t affected at all so if you wanted the player to step on the roots you would have to manage that a different way.

[@LastIberianLynx_GameDev]

Thanks. We need more of this stuff. One thing i have some difficulty when dealing with these effects is how to control them from Blueprints. I normally lerp the material parameter but this doesnt seem ideal. Is there any way to trigger this animation, without having to lerp the variable manually in BP? Or thats just the way to go? Kind like there should be way to do it in the material itself.

[@Tylru]

Best to animate it in sequencer and save that out as an animation you can play from Blueprint :)

[@kettenotter]

The best way is using a timeline in an actor. Then you have the most control. You can also just update the custom primitive data instead of using an extra Material instance. Actually the best way is probably using Niagara particle system. Then you have the most Flexibility and Performance. You can just spawn a single particle for the root mesh. (This is actually the setup I use for this kind of effect)

[@Fafmagic]

Would using material parameter collections work better?

[@tharlevfx]

You can animated the parameter directly in sequencer if it’s just for a cinematic or portfolio piece. Or a material parameter collection could work too. In blueprint I would probably use a timeline and drive the parameters that way, or if it’s something like a gameplay effect you could use niagara and spawn these as mesh particles with animated material parameters - lots of options, it just depends on your use case :)

[@kettenotter]

@@Fafmagic I am not a big fan in this case. Because if you later want two instances with different values it gets messy. Use it more for things which are everywhere the same: Light direction, Fog color, Time of day, season...

[@carlosrivadulla8903]

is a pity that someone like u doesn't use houdini to leverage all that math and fundamentals knowledge.

[@tharlevfx]

I’ve tried to learn it a few times but I just don’t need it for most of what I do. It’s a great tool for films but a bit too much for most games projects