adding two masks for fire outgoing velocity

[cb LLC]

Hi
We have a barn on fire. To break up fire pattern we use noise for outgoing velocity. We also putting out fire using reverse wetmap. How can we add two masks? One for noise and the other one for where wetmap hits the wood we need to have no fire at all. SO wetmap must override noise texture even where white spots of noise are on fire. Please could you give us a sample file with 2 maps inside outgoing velocity?

2. The second question: The bard is big. So doing upclose in high res is challenging. Do I have to constantly change my grid size and position only where the camera is? I am trying to have full barn on fire and have different camera angles but the resolution is the biggest phoenix obstacle. I wish it was procedural resolution

Thank you

[Svetlin.Nikolov]

Hey,

So you just need to multiply the noise by the reverse wetmap - this way the emission would be only where both maps are white. Without V-Ray maps, maybe a Composite map with Multiply mode would help?

As for having the camera up close, maybe several simulators would allow you to have higher res only for those near the camera?

Cheers!

[cb LLC]

Hey,

So you just need to multiply the noise by the reverse wetmap - this way the emission would be only where both maps are white. Without V-Ray maps, maybe a Composite map with Multiply mode would help?

As for having the camera up close, maybe several simulators would allow you to have higher res only for those near the camera?

Cheers!

Hi,
i tried but nothing works. We tried using 3ds max standard map. Are we doing something wrong/

Wetmap create white background overriding noise but then if i hit reverse I will get fire where wetmap is even though it is supposed to be the opposite
I attached my map file
Thanks

[cb LLC]

I think this set up worked

[cb LLC]

Hey,

So you just need to multiply the noise by the reverse wetmap - this way the emission would be only where both maps are white. Without V-Ray maps, maybe a Composite map with Multiply mode would help?

As for having the camera up close, maybe several simulators would allow you to have higher res only for those near the camera?

Cheers!

Hi Svetlin,
So using noise as mask has no affect on performance but wetmaps drop it from 7 sec per sim frame to 1 min 17 seconds. I know we talked about it a long time ago. I wonder if there is anyway I can adjust particle texture settings or you guys can improve it on your side, 7 sec vs 1 min 17 sec is a big big difference. It will take forever to simulate. Not sure if there is any other way to put out fire

Also I noticed if fire grid is 10 mil cells without wetmaps it is 3 sec with wetmaps 7 sec. When grid is scaled to 40 mil it goes from 7 sec (no wetmaps ) to 1 min 10 sec. A very big jump Not sure why since liquid wetmap grid is the same size and wetmap is only used to block off parts of fire

UPDATE: Changing blending method from proportional to equal sped up sim from 1 min 17 sec to 27 seconds. I guess solid color is faster than gradient. Increasing particle radius helps too Still slow though


BUG UPDATE:
There is a bug where if you simulate while wetmaps are present and then change sim time before wetmaps are available sim speed will be as slow as it has wetmaps,. Max must be restarted to fix

[Svetlin.Nikolov]

The particle texture needs to read the wetmap particles from the caches on the hard disk and then the mapped source reads that data and searches for particles near each emission point - indeed this is slow...

How can we reproduce the slowdown issue here? Should the liquid simulation start from a later frame than the fire/smoke simulation?

[cb LLC]

The particle texture needs to read the wetmap particles from the caches on the hard disk and then the mapped source reads that data and searches for particles near each emission point - indeed this is slow...

How can we reproduce the slowdown issue here? Should the liquid simulation start from a later frame than the fire/smoke simulation?

Hi, I attached the scene
Steps to reproduce
1. Simulate liquid
2 Simulate fire with COMP MAP (it combines noise and wetmap for barn fire mask) Start from frame 240 where wetmap already exists.
3. Stop adjust grid to a bit higher resolution.
4. After simualting 20-30 frames stop and start simualting from frame 100 (before wetmap is available)
You should see it if you go back and forth. Also try replacing comp map with noise only and later back with comp map

Doing this back and forth slowed me down. So after slow wetmap simulation at frame 240 when i went to frame 100 to sim it was as slow as frame 240.
Please change phoenix texture map to proportional blend to have the most slowdown

Thanks



UPDATE:
just did another grid movement, resizing etc Speed was 2 mil after resting max it went to 4

[Svetlin.Nikolov]

Ahhh, watch out! You have two simulators - liquid and fire.
1. When you simulate the liquid simulator, it does its thing; You get a warning that the Fire source would affect the liquid simulation. This is important - if you don't want to get unexpected results, make sure that each simulator includes only the sources it interacts with, or alternatively - excludes all sources it does not interact with.
2. When you run the fire simulator, it interacts with the result from the liquid simulator. Each simulator sees the other simulators in the scene as obstacles, in the shape of their meshes/isosurfaces. You can enable the mesh preview of simulators in order to figure out how other simulators would see them, even if they don't render in Mesh/Isosurface mode. Just like any other geometry in the scene, a simulator would be an obstacle for other simulators if it's set in Solid mode, and this is by default. Also, here you again have the potential issue from step 1 - but this time the opposite case - the liquid source would affect the fire sim if its emitters enter it.
3. When you run the liquid simulator again, it would behave differently. This is because now the fire simulator has caches and starts to be seen by the liquid sim as an obstacle.

Always remember - when simulating overlapping simulators, first decide on the order in which they would be affecting one another, and exclude from interaction all simulators that should not affect a simulator back - you can use either Exclude or Include mode under the interaction rollout, in case you get circular reference errors. Remember that if you need Include mode, you gotta include all sources, all of their emitters too, all obstacles, all forces affecting a simulator.

We've got a page on the docs site summarizing the different ways simulators: https://docs.chaosgroup.com/display/...een+Simulators

Does this help?

[cb LLC]

Ahhh, watch out! You have two simulators - liquid and fire.
1. When you simulate the liquid simulator, it does its thing; You get a warning that the Fire source would affect the liquid simulation. This is important - if you don't want to get unexpected results, make sure that each simulator includes only the sources it interacts with, or alternatively - excludes all sources it does not interact with.
2. When you run the fire simulator, it interacts with the result from the liquid simulator. Each simulator sees the other simulators in the scene as obstacles, in the shape of their meshes/isosurfaces. You can enable the mesh preview of simulators in order to figure out how other simulators would see them, even if they don't render in Mesh/Isosurface mode. Just like any other geometry in the scene, a simulator would be an obstacle for other simulators if it's set in Solid mode, and this is by default. Also, here you again have the potential issue from step 1 - but this time the opposite case - the liquid source would affect the fire sim if its emitters enter it.
3. When you run the liquid simulator again, it would behave differently. This is because now the fire simulator has caches and starts to be seen by the liquid sim as an obstacle.

Always remember - when simulating overlapping simulators, first decide on the order in which they would be affecting one another, and exclude from interaction all simulators that should not affect a simulator back - you can use either Exclude or Include mode under the interaction rollout, in case you get circular reference errors. Remember that if you need Include mode, you gotta include all sources, all of their emitters too, all obstacles, all forces affecting a simulator.

We've got a page on the docs site summarizing the different ways simulators: https://docs.chaosgroup.com/display/...een+Simulators

Does this help?

Thanks. Well the liquid was simulated before fire grid was even created (and fire uses wetmaps from liquid to show where fire needs to be put out). It's when fire gets simulated it can go around 4 mil vox per sec and after moving grid around, tweaking settings in dynamics, changing a different start changing textures and then sim again it can drop to 2 mil and after restarting max it would go back to 4 mil. It doesn't happen all the time. It is strange that after rebooting the same frame simulates twice faster. Clogged ram?

[Svetlin.Nikolov]

Could be, gotta run some more aging tests here as well. There aren't any moving geometries in the scene, right? So the exotic things would be simulators interacting, mapped sources and texture calculations, which have certain pitfalls too...

But always make sure to exclude interacting simulators in one direction and also their interaction sources, of you will be in for strange surprises.

[cb LLC]

Could be, gotta run some more aging tests here as well. There aren't any moving geometries in the scene, right? So the exotic things would be simulators interacting, mapped sources and texture calculations, which have certain pitfalls too...

But always make sure to exclude interacting simulators in one direction and also their interaction sources, of you will be in for strange surprises.

no moving. I noticed resizing grid, lowering res and then sim, Then up-scaling grid and sim it causes slow down until max is restarted

[cb LLC]

Could be, gotta run some more aging tests here as well. There aren't any moving geometries in the scene, right? So the exotic things would be simulators interacting, mapped sources and texture calculations, which have certain pitfalls too...

But always make sure to exclude interacting simulators in one direction and also their interaction sources, of you will be in for strange surprises.

Hi Svetlin,
you guys promised to make a tutorial a house on fire and fire truck putting it out. Would be nice to see how to make a good looking blaze and liquid and steam/smoke, collapsing studs that create particles. Please make it.