View Full Version : HV shadows

02-01-2011, 08:37 PM
I have made a pretty realistic fireball HV preset, the onlything standing in my way being that ialways casts shadows on itself, and I don't like that, for obvious reasons. So I changed the shading to "self" and turned off volumetric shadows, and it's looking much better, except where it would normally cast shadows, it doesn't look as luminous. PLS help.

02-02-2011, 01:37 AM
a picture between the them two..the one with shadow cas and the one without volumetric shadow could help, for us to see whats up.

for fireflames you really donīt need volumetric shadows, you might want that on thick smoke thou.


02-03-2011, 12:34 PM
Hmmm... I just takes so long to rendeer. I'll atach the .lws file.92463

02-03-2011, 02:09 PM
The scene is missing all the objects..lol:)

Yeah quite heavy render time, Im just checking how to reduce that first and I notice that you have radiosity on, so the question is if you really need that for the scene?

Next is that you have very large particle size, reduce size to something like 15 meters or lower perhaps and use a particle age gradient on the size to scale up only at the end frames where particles break up.

Then you have the highest quality mode for voxels wich I believe wouldnt be necessary.

You are also using all lights checked wich most likely needs to be calculated through the voxels and with that extra render time, so I would only use one or two lights affecting the voxels.

have to hit the sack now, so I havent really checked in to your actual question.


02-03-2011, 02:19 PM
I noticed that You have a lot of particle spawning objects in there aswell, but not active for hypervoxels, the one you are using (fireball) only reaches 50 particles, I would probably use quite a lot more.

What explosion look are you after? you could probably use only sprites for the explosion in space.


02-03-2011, 04:36 PM
I prefer less particles so it loses it's shpere type look

02-04-2011, 01:40 AM
I prefer less particles so it loses it's shpere type look

Yeah I understand what you mean, but you would get that round blob look anway when the particles stray away at the end, unless cutting through the hypertexture very much with hypertexture strenght or lower density etc and a couple of big particle voxels at the end wouldnīt look nice if they are to few.

I would suggest using a few particles as trail carriers shouting out and having child emitters parented with quite some vibration on them, that will give a look of pillars blasting out, and a combination with some fewer particles wich is fast and short lived just giving the ( spherical) initial blast.

Additional smaller particles with smaller trails and even more faster sparkle particles shooting out would make the explosion multilayered and a little complex but also more realistic me thinks.

02-05-2011, 03:41 PM
in "avatar" explosions looked like they were few particles.

02-05-2011, 03:44 PM
in "avatar" explosions looked like they were few particles.

I donīt know, but I beleive most of that was probably fluids.


Mr Rid
02-06-2011, 05:38 AM
As Prom mentioned, I would use the lowest Render Q setting, and not use any lights to illuminate the fire but instead crank up luminosity. Will speed renders a lot, and fire is self illuminating and should not receive shadows. Also you dont want fire settings you like to be stuck to a specific light setup that wont work in other scenes. GI is slowing render time way down for no benefit since you have Volumetric Radiosity disabled in the Render Globals.

Btw, the difference between Avatar explosion tools and LW's is like the difference between shooting a bullet, and throwing it.:)

02-06-2011, 09:17 AM
As I understand it and what I know of, most of the space explosion scenes seen around..as in battlestar galactica, are made of different layers and often combined with real explosion footage like Artbeats footage, in the end for that "extra realism"
Then thereīs the underlying spark particles and particle trails with hypervoxels and perhaps some initial particle blast that are very short lived.

The old starwars explosions were filmed stuff and copied in to the filmed plates.

You could go and get Sean M jacksons Videotutorials at kurv studios if you can afford it, he worked on galacticta with explosions etc..or check Dj lithiums tutorials on liberty 3d.

And indeed in Avatar they couldnīt use filmed footage, since the 3d aspect of it and thus had to be completly CG elements and there for used
fluid tools developed in earlier projects such as poseidon.

You can read a little about that here...almost at the end of the page is the topic regarding CGI explosions

Thereīs a difference in scene construction environment and thus how
explosion behave when you look at battle star galactica vs Avatar..
Avatar is set in a more Air atmospheric than outer space and the explosions need to be more down to earh heavier explosions, wich fluids might be more suitable for.

I guess we still have to wait a long time before any training material will show up for those earthly explosions and especially working with fluids, since whatīs available for lightwave "turbulence" is still in itīs beta stage and not many people have been using it.
Thereīs of course many things that are alike from different fluid systems wich could be of practise to use in turbulence as well.

I would suggest downloading the turbulence demo and start learning a little about it, changing some parameters such as pull down wind forces, expand the heat and normal settings etc, that can get some basic explosion outwards with a more realistic dynamic motion than with particles.

Then again, fluids might be a little more complex to learn and get right than using particles for begginers.