Burning Cigarette

[TAkin]

Hi there, I'm trying to achieve an effect like in the link below:

I have in the past tried using SDFs and now using the cloth solver. Any insights on this will be appreciated. I have also attached my .hip file.

[TAkin]

Scene file here.

Cigarette_Burn.hip

[woodenduck]

Have you checked out Peter Quint's Sop Solver tutorial? He takes you through how to create a burning match, very similar effect essentially.

http://vimeo.com/6660287

WD

[TAkin]

Have you checked out Peter Quint's Sop Solver tutorial? He takes you through how to create a burning match, very similar effect essentially.

http://vimeo.com/6660287

WD

Thanks for your reply. Yes I have. That was useful to an extent. For the decompostion effect, what he did was to simply move points along their normals which I could equally have done with a peak SOP, mountain SOP or a VOP SOP. But an real cigarette actually is between a rigid body and a softbody and it tears and crumples as it burns.

[Peter Quint]

I think the SOP solver tutorial might be a bit misleading. I chose the burning match as a way of illustrating the SOP solver - but as I think I say at the start of the video the SOP solver is not the easiest way to do this.

I've not tried to construct a burning cigarette myself. But I guess I would separate out the elements:

- the smoke rising from the burning end;

- perhaps some flames or embers at the burning end;

- the fact that the cigarette gets shorter, and possibly changes colour;

- and perhaps some ash falling off the end and accumulating on the ground / table or whatever;

I would create/sim these separately. The smoke source for example can be an animated box volume which you multiply with a volume representation of the cigarette using volume mix - the box moves along the length of the cigarette as it 'burns'. The flames or glow at the burning end could be achieved in a similar way, though I would keep this as a separate sim.

The cigarette getting shorter is in some ways the most challenging part. You could probably do it with a clip sop and a separate 'burnt end' which again is animated to move inwards as the cigarette shortens. The burnt end would need some time varying randomness to make it look right.

For the ash you might take a version of the cigarette, fracture it, then make the pieces successively become sources for a particle sim for the ash. You might do this by assigning frame numbers to each successive fracture piece (the connectivity SOP will help). I think my Flying Letters video covers something like this. You can use the same method to make each piece disappear (as part of the shortening stage above).

Of course you would need to coordinate the animation of the various parts / boxes / frame numbers to make it look like a single process.

I realise that's a rather complex and high level description, but I hope it helps to get you started.

Peter

Edited August 22, 2012 by Peter Quint

[TAkin]

Hi Peter. Thanks for the very detailed response. I will use these as a guide and will see the results I will be able to come up with.

I tried to achieve the cigarette getting shorter effect by subtracting SDFs. I have attached a file for your viewing. The noticeable problem with this approach is that the other end of the match seems to be morphing and seems to be visually distracting.

Once again, thanks for your reply.

Tosin.

subtracting_SDFs.hip

[Peter Quint]

I haven't tested the SDF method. Here is another method for the shortening using the ray sop.

collapse.hip

[TAkin]

I haven't tested the SDF method. Here is another method for the shortening using the ray sop.

Hi Peter,

I find this approach very intuitive. I will combine all of these techniques you have suggested and I'm sure I will be able to achieve the desired effect.

Thank you very much once again

Tosin

[Diego A Grimaldi]

Did you ever finish that effect? A hip file would be awesome

[TAkin]

Hi Diego,

 

No, I could not get the solution I was after. The closest I could get back then was this  

 

I also played around with the FEM solver after its introduction into Houdini last December.

 

I think you might find these links helpful though as I have not had the time to pursue this in a while but the project is still actively on my mind:

 

http://ihoudini.blogspot.com/2013/11/sop-solver-cloth-tearing.html

http://ihoudini.blogspot.com/2013/12/worm-locomotion-with-fem.html

 

Kindly let me know if you do find a solution.

 

Cheers!

Tosin

[Diego A Grimaldi]

Cool, thanks for the reply! I'm actually trying to do something a little bit different, I actually need to model the cigarette ash, I'm not concerned much about the animation.

 

I've actually just made a post here:

 

http://forums.odforce.net/topic/20730-cigarette-ash-procedural-model/#entry123761