liquid nitrogen

[roughsporty]

I try to get a liquid nitrogen effect which coming out of a cauldron and falls to the ground and fades away.

So would be great someone can point me in the right direction? SHoudl I use a smoke container or the pyro effects?

Thanks

[mightcouldb1]

I used a high cooling rate, not sure if I used a negative buoyancy. You can use the smoke or pyro. Both will get you there. Add a good amount of turbulence and vorticles. As for the fade out when it hits the ground, you could time the dissipation or you could just use a volume with smooth transition to subtract the density from the smoke in SOPs.

Not the best test, but I think it might be similar to what you are looking for:

[roughsporty]

Yes, that is what I try to achieve and thanks for your good amount of input. It seems that it's not so difficult to do. I will post here my first test, when its done.

I used a high cooling rate, not sure if I used a negative buoyancy. You can use the smoke or pyro. Both will get you there. Add a good amount of turbulence and vorticles. As for the fade out when it hits the ground, you could time the dissipation or you could just use a volume with smooth transition to subtract the density from the smoke in SOPs.

Not the best test, but I think it might be similar to what you are looking for:

[roughsporty]

I have setup a test scene for my project. The cylinder is filling with smoke but it seems that it stops and not rising up.

smoke_filling_test.hipnc

[mightcouldb1]

You don't have any force pushing it up. That will help a lot. I used a circle on the XZ plane, scattered points on that, added normals facing up, then imported those into DOPs using the SOP Geometry DOP connected to a Field Force DOP with "N" as the force. Make sure to scale the force quite a bit, since the normals are unit... Although I supposed you could scale the normal in SOPs as well. Same effect. Hope that helps!

[roughsporty]

You don't have any force pushing it up. That will help a lot. I used a circle on the XZ plane, scattered points on that, added normals facing up, then imported those into DOPs using the SOP Geometry DOP connected to a Field Force DOP with "N" as the force. Make sure to scale the force quite a bit, since the normals are unit... Although I supposed you could scale the normal in SOPs as well. Same effect. Hope that helps!

Hi Jason, I have followed your tips and I have now a SOP Geometry DOP which goes into the Field Force DOP but I have no idea where to connect the the Field Force DOP in my actual DOP structure. Maybe before the smokesolver? Thanks for your help

Thies

[mightcouldb1]

You can usually add forces at the end of your network and get the desired effects.

[roughsporty]

I think I setup the connections in DOPS right but there are no changes. I put my file here

smoke_filling_test.hipnc

[mightcouldb1]

You set up everything right. The force is just extremely low. If you scale your force to 1000 you'll see some obvious results.

[roughsporty]

ah, that's look's better so in the next days I have a lot of time to tweak things.

But how works the force field exactly? Each scattered point will be used to evaluate the force? The force looks noisy but I think its actually not

[mightcouldb1]

The force pushes along that vector that is the normal, so in the areas where there are no normals there will be less force. That is why you can get the appearance of turbulence. You can increase the amount of points that you scattered to get less of that. A volume based solution might be a good route to take as well. I'll try to put an example together later today if I have a chance. You can use a volume gradient from file in a VOP Force DOP. You'll get a smoother result that way than using the point normals as the force. I like the effect that the normals give but it can be difficult to control.

Edited June 1, 2010 by mightcouldb1

[roughsporty]

The force pushes along that vector that is the normal, so in the areas where there are no normals there will be less force. That is why you can get the appearance of turbulence. You can increase the amount of points that you scattered to get less of that. A volume based solution might be a good route to take as well. I'll try to put an example together later today if I have a chance. You can use a volume gradient from file in a VOP Force DOP. You'll get a smoother result that way than using the point normals as the force. I like the effect that the normals give but it can be difficult to control.

I have made several test mainly with the force, buoyancy lift and the cooling rate. A little bit like trial and error and recook the simulation but from that I have learned much. The worst thing is the recooking. With to less smoke resolution

it is hard to decide if it's a good result so I work with a resolution of min 60 to test.

Would be great to have an example to get different approaches,

Thanks

[mawi]

I have made several test mainly with the force, buoyancy lift and the cooling rate. A little bit like trial and error and recook the simulation but from that I have learned much. The worst thing is the recooking. With to less smoke resolution

it is hard to decide if it's a good result so I work with a resolution of min 60 to test.

Would be great to have an example to get different approaches,

Thanks

I use to start of with a 2d container. This will give you fast feedback with high resolution while testing.

[roughsporty]

The force pushes along that vector that is the normal, so in the areas where there are no normals there will be less force. That is why you can get the appearance of turbulence. You can increase the amount of points that you scattered to get less of that. A volume based solution might be a good route to take as well. I'll try to put an example together later today if I have a chance. You can use a volume gradient from file in a VOP Force DOP. You'll get a smoother result that way than using the point normals as the force. I like the effect that the normals give but it can be difficult to control.

can you give me the example please?

thanks