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stig_olsen

Emit smoke from point in the middle of a chunk

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Hi,

 

I want to emit smoke from my chunks, and I want it to emit from a point in the middle of the chunk. Is that possible? The reason why I want that is because if I emit from an entire chunk the smoke will get very massive.  H13.

 

Stig

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Hi Stig!

 

What I usually do in that case is to feed my chunks into a forEach and inside it using a point SOP give my points the centroid() as position... then I just fuse all together!

 

Another thing you can try (but IMO it will not be the exact middle of the points) is to get from a dopimport just the points, write them out (write out also from the forEach to save time ;) ) and use them to emit smoke...

 

Hope it helps!

 

Cheers

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Perfect, it works perfectly using the foreach and the point SOP!

Is it a way to emit smoke from these points using the Billowy Smoke (it emits only from geometry) but having it emit from my points instead?

 

Stig

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Hi Stig!

 

I'm not able to test it right now but can do it later on... however if I'm not mistaken, you can/used to be able to select emit from points... if not, trick it ;) give it some geo to emit from and then replace the object (path and/or real object) by your points...

 

I'll try to do it later if I can to show you!

 

Cheers!

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Thank you Santos.

 

I think the Billowy Smoke only can emit from geometry so I think it need to be tricked as you say. I cannot find a way to do it.

I have attached my project, and it is set up to emit from the geometry of the chunks, and as you understand - I need to change this to emit from the center points of each chunk instead. And while you are looking at it... any good settings for making the trails looking more like trails?

 

Thank you very much, I really appreciate it!

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Hi Stig!

 

I'm going to try and look at it now... anyway, regarding your second question of the settings for trails... I haven't checked the file yet so I'm just asking... have you set up any motion Blur on your fluid source? I don't know if you have seen Peter Quint videos on Smoke in H12 (these setting apply, as far as I know...) Check this one, around 9 or 10 minutes into it https://vimeo.com/38288672

 

Cheers!

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The main problem you have there is a voxel size of over 2 meters, your chunks are much much smaller than that. Here's a bit fixed scene, with a resolution of 0.05 meters, plus some other fixing. As J.Santos says above, the motion blur tab in the create_density_volume node is your friend.

post-2678-0-12158100-1395671098_thumb.jp

center_points_v2e.hipnc

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Ok Stig!

 

I never got around to check it, but eetu has replied and tweaked it!

All the best!

 

Cheers

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Hi both, and thank you for helping me!

 

The project file I got back is to heavy to read even for my z820 machine. I would be really glad if you instead can spell out what you actually did regarding my two problems:

 

1. I  want to emit Billowy Smoke (it emits only from geometry) from the centered points I made instead of geometry. Santos, you had a workaround, a way to trick it?

2. How big lines of how to make the trail look like trail? I guess it has nothing to do with the size of the box...?

 

Stig

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If you want to do high resolution sims, you will need to learn to wait ;)

That said, try 0.1 for the res, it should be quite a bit faster (although more blobby..)

 

1. The main things I did was to plug your foreach into the create_density_volume node, adjust the point stamp resolution as well as the whole sim resolution, and added samples to the motionblur parameter there.

 

2. check the size of your flying chunks, the size of the emitted trail should be close to that, no?

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Thanks! It certainly works good to plug the foreach into the "create density volume" node,

 

What I find a bit strange is that it looks like only some of the chunk points emit trails.

And, those trails that are emitted from the chunk points doesnt look at trails at all, its like if the smoke is bleeding out. (it looks good on your example, but not mine)

 

I cant find that the resolution or the motion blur has that big influnce over this.

 

I have attached a project file if you will so nice and take a look at it again.

 

Thanks, Stig

center_points_v3.hipnc

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