Particles suggestions

[Amerio.Stephane]

Hello, a few suggestions for particles:

• when using an ObjectMeshCluster as a child of a Particle emitter, the size of the generated meshes can only be controlled through the "growth" coefficient. It would be nice if the birth size could also be controlled through the "Radius" parameter.
• A particle material can be set to use refraction, but not "transparent blur". This would be a great addition to simulate hot hair blazed from turbines (the real world visual clue is the blurriness, not so much the refraction, see here: https://st3.depositphotos.com/1671840/13258/i/1600/depositphotos_132588334-stock-photo-nh90-navy-helicopter-take-off.jpg )
• particule atlas always use a 4x4 grid. Is it configurable ?
• particle procedural rendering: not described at all in the doc. Can't seem to make it work :(
• variation x/y: described in the doc, but I can't make it work. Am I missing something obvious?
• particles collision with water. It does work, but particles still always end up drowning and disappearing (I wanted to use them for a oil/debris left from ship); Can we control the buoyancy of the particles ?

Thanks

[vvvaseckiy]

Hello, Amerio.Stephane

On 8/3/2018 at 4:31 AM, Amerio.Stephane said:

when using an ObjectMeshCluster as a child of a Particle emitter, the size of the generated meshes can only be controlled through the "growth" coefficient. It would be nice if the birth size could also be controlled through the "Radius" parameter.

Unfortunately for now birth size of generated meshes can only be controlled by scaling of meshes itself

On 8/3/2018 at 4:31 AM, Amerio.Stephane said:

A particle material can be set to use refraction, but not "transparent blur". This would be a great addition to simulate hot hair blazed from turbines (the real world visual clue is the blurriness, not so much the refraction, see here: https://st3.depositphotos.com/1671840/13258/i/1600/depositphotos_132588334-stock-photo-nh90-navy-helicopter-take-off.jpg )

I've added task for implementing transparent blur in particles material to our internal bugtracker. It should be added in 2.8 release

On 8/3/2018 at 4:31 AM, Amerio.Stephane said:

particule atlas always use a 4x4 grid. Is it configurable ?

For now it is not configurable, i've added task for expanding atlas limitations to our internal tracker. Unfortunately i can't give you any ETA when it will be done.

On 8/3/2018 at 4:31 AM, Amerio.Stephane said:

particle procedural rendering: not described at all in the doc. Can't seem to make it work :(

There are multiple ways of implementing procedural rendering. For example using particles procedural texture as mask for decal. To get this working you need set orthographic as child of a paricle system. Then enable Procedural Rendering and set Procedural Parenting parameter = Children. From now on decal will be rendered according to procedural texture generated by paricle system . Procedural Positioning Parameter sets affected node position, manual positioning should be optimal for decal case. We will update documentation on using Procedural Texture feature in short terms. 

On 8/3/2018 at 4:31 AM, Amerio.Stephane said:

variation x/y: described in the doc, but I can't make it work. Am I missing something obvious?

Variation seems to be working correctly in 2.7.2, could you please describe in which case it doesn't work?

On 8/3/2018 at 4:31 AM, Amerio.Stephane said:

particles collision with water. It does work, but particles still always end up drowning and disappearing (I wanted to use them for a oil/debris left from ship); Can we control the buoyancy of the particles ?

Unfortunately you can't control buoyancy of particles with global water. You may implement oil spots with using procedural texture feature described previously. And for the debris it'll be easier to use meshes with physical bodies, you can check out exaple of objects with similar behaviour in Oil Platform demo or Syncker Demo. 

Thank you for your feedback

[Amerio.Stephane]

4 hours ago, vvvaseckiy said:

For example using particles procedural texture as mask for decal

I tried exactly what is described, and I can actually see the particles used as a mask for the decal, but not for the projected color: It stays (almost fully) black:

If I add a Detail layer in the decal, then the decal turns completely white. I tried all sort of combination and sliders values, I can't get something "logical" to me, so obviusly I'm missing something here. Is there a demo of it outside of the Oil Platform/ship sample ? (because everytime I try to uderstand it, I need to "expand" the ship reference, and this makes all particles disappearing).

4 hours ago, vvvaseckiy said:

Variation seems to be working correctly in 2.7.2, could you please describe in which case it doesn't work?

It doesn't work if Texture Atlas is enabled.

4 hours ago, vvvaseckiy said:

Procedural Positioning Parameter sets affected node position

I now understand how this works, but wouldn't it be nice if it AUTO would control not just the vertical position, but also the x/y and the size of the decal node to encompass all particles? Just thinking, after reading all the ship.h code in Oil Platform to manage the decal node side.

Thanks for your help.

[vvvaseckiy]

Hi,

While using procedural texture almost all adjustments done in Particles System, you need to set diffuse texture to particles material, and enable emission for it to render correctly. For now there's unfortunately no additional examples of particles with procedural texture, but for 2.8 release we have planned major rework of creators menu, from which you will be able to create preconfigured particle-decal systems
 

15 hours ago, Amerio.Stephane said:

It doesn't work if Texture Atlas is enabled.

I've added this bug to our internal bugtracker, but unfortunately i can't give you any ETA when it will be fixed.

16 hours ago, Amerio.Stephane said:

I now understand how this works, but wouldn't it be nice if it AUTO would control not just the vertical position, but also the x/y and the size of the decal node to encompass all particles? Just thinking, after reading all the ship.h code in Oil Platform to manage the decal node side.

Are you implementing particles with procedural texture from code? From editor 2 it seem that AUTO procedural positioning correctly adjusts width and height of ortho decal.

Thanks
 

[Amerio.Stephane]

Increasing the emission value of the particles did the trick ! Thank you !

For the AUTO resize, you are right, it also adjusts width and height of the decal. I was mislead by the OilPlatform, which uses a reversed Decal/Particles hierarchy. By using Particles/Decal (child relationship) everything makes senses now :)

Thank you !