Smoke in RF6

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Knife Edge Software Owner
We made some pretty significant changes to the smoke for RF6. Here is a quick rundown of what they are:

Texture change:
smoke particles in previous versions were very wispy. For RF6 we made the particle textures much brighter and more solid. The benefit of this is it allows us to make the smoke look dense without having to add a lot of particles to the scene. The result is a much faster rendering and a more realistic image.

Particle size:
After some review we determined that the particles were not sized correctly. Particles in RF6 are larger than in previous versions. Increasing the particle size allows us to draw fewer particles, which is a performance improvement. The downside to this change is that aircraft built for previous versions will have larger smoke than intended when run in RF6.

Particle tint:
Particles are now tinted to model, in a simple way, the scattering effect of light. You will see a subtle blue/brown shading of the particles.

New "Ejection Velocity" and corresponding direction properties:
You can now have a smoke component emit the smoke with a starting velocity and direction. You can see how we used this on the 35% Sbach, to simulate pyrotechnic smoke in the wingtips.

Limitations of the Smoke System
Note that for performance reasons, the airflow lookup for each particle is performed only once, right at the moment it is created. Therefore, no matter how the particle passes through the prop wash, this will not change the direction of the particle's movement. In other words, while the stream of particles may curve, individual particles move in a straight line, always, unless they hit the ground.

Also, particles are not deflected by solid objects, including the aircraft and scenery objects. Smoke particles simply pass through these things.

Another limitation is that there is only one layer of transparent texture available to the rendering system, for performance reasons. Therefore you may notice that when there are two overlapping transparent things (e.g. smoke and canopies), they will not be blended together but rather only one will be drawn. This is most noticeable with the Sbach's wingtip smoke.

These limitations aren't new to RF6, I just wanted to mention them to everyone. We are investigating solutions for these shortcomings but can't make any promises because of the performance implications.

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