http://www.videocopilot.net/tutorial/explosive_training/p3/ [videocopilot.net]

Hey guys, I have a feel for Houdini, but I'm still lacking the capability to make something like Andrew did in this tutorial. I've taken a bunch of peter quints tutorials and they are great, but I feel like I need a more directed path to make something like this. Is there something out there that I can read up on\watch to learn how to do this? Or can someone teach me?


Thanks

How far are you looking to go? Do you have a hard time just doing the simulation? The rendering? Camera tracking? Comping it on top of live footage??? How far have you gotten in your own tests so far? Can you post what you're working with so we can maybe give you some good direction?

I find that a lot of the concepts behind doing an explosion in one app are quite transferable to another. You have a source, you give it some fuel, velocity and temperature and let ‘er rip. Of course each app has it’s own workflow, but it can a lot of the time come down to: tweak, sim, tweak, sim, tweak, sim… etc. Take a look at the explosion shelf tool. Start there, study some of the settings they've set, and tweak it to your liking, etc. Also take a look at the volcano tutorial: https://vimeo.com/44129053 [vimeo.com] Either way, the more you do it the better of an idea you'll have as to what's going on and how to get from a to b sooner.

Hey Thanks a lot. Yeah I know how to comp pretty well. What I want to know is how to get simulations rendered out good like that.

For starters how would I do what he does, he shapes the particles and then those particles emit. So in H12 how do I set that up? I would like to know how to get the particles to emit pyro, smoke and all that and then bring it into the container. How do you usually go about setting up your sims? Do you have any work you can share so I can ask more relevant questions? I ask this b\c I have trouble simulating things like missile trails or a ball on fire moving, stuff that is static like a volcano I can do the simulation. And I can never get my fire with smoke to render looking right, do you have any tips on this?

The volcano tutorial was great, I watched a couple months ago, I'll watch it again soon.


Thanks for all the help

Also, quick side question, how do you change the render background to gray? I forgot this and can't find the answer on google :O

Particles – you can set up a pop net pretty quickly in Houdini. The big thing to note is that you basically need some point velocities. You can actually customize point velocities rather easily in Houdini without actually having a point move. Vop Sops (and vop pops) are really good for adding noise and direction to point vels. It's a little daunting at first, but super useful later. You should probably just start with a sphere emitting particles in a specific direction, all doable from pops. For getting them into pyro, you can start with something like the flames or fireball shelf tool, disable the default source that gets created with that shelf, and use the ‘source from points’ tool on the Volume fluids shelf. This will create the nodes necessary to source from your points.

I tend to work more with objects/volumes, using particles or point velocities as necessary to help guide my fluid. In max you don't have arbitrary point velocities that can affect your sim, so you have to use an actual particle system to get that information. I don't have much pyro (I think only the one, and it's not very impressive) on my vimeo: https://vimeo.com/user4342373/videos [vimeo.com] but I've used it in production quite a bit over the past few years – though generally not for explosions (did a fireball a few months ago), and not for rendering. I'm def not an expert at rendering in Mantra yet. The Pyro shader is quite extensive, but here are some videos that help break down the nodes and what is going on behind the shader – as well as a video describing the pyro shader itself here: http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&p=117096 [sidefx.com] I think scattering is generally the key to getting good looking fire/smoke. Adding noise to the fire in shading can help add nice details too. I personally tend to stay away from adding noise to smoke in the shader, preferring to use sim resolution to get details, but if done right you can add some good detail that way too.

For Missile trails, you should look into the new clustering tools. Also, you'll likely need oversampling, or a customized source to help with substep issues.

You want to change the viewport background or the render? Viewport you can point to a cop node if you want or point it to a file. Press d in the vp to bring up the options. In the render, you'll have to have a file on disk I think, and press d in the render view to bring up background options. I don't know how to render with a color or image in the bg already, outside of putting a constant shader on a big sphere… Hope that helps a bit…

Great! thanks a ton for helping me out. I've got a ton of tutorials on houdini I just need to get serious with this now and starting learning this beast in and out. I started using Maya in 2006, and C4D in 2011. For the rendering a BG color its super easy in Maya and C4D, was wondering if there was a option like that in Houdini .


“For Missile trails, you should look into the new clustering tools. Also, you'll likely need oversampling, or a customized source to help with substep issues. ”

Do you mean when you click on the autodop node when you are at sops level and tweak with those settings?


Also, I might be bringing this topic back from the dead in about 2 months when I've learned more and have more better questions to ask .

Again, this helps means the world to me, TY.

For the missile trails, what I mean is usually a missile is travelling fast, so if you use default settings your emitter will have traveled very far between frames, leaving huge gaps in emission. There are quite a few ways to handle this. The most straightforward, but slowest is to increase the number of substeps the dop network takes, which will force it to calculate your geometry in between frames. The other way is to use sops to manipulate the source to cover a larger area. Quick ways to do this is to use the trail sop to make a copy of the source geometry between frames, or there is also a ‘blur’(not sure the name of this at the moment) option on the fluid source node in sops that can create a volume out of substeps for you as well. It's better to do it in sops, so the dop network, or pyro sim doesn't have to do as much work. You don't want the pyro sim to calculate everything 4 times per frame if you don't absolutely need it, so manipulating the source geometry to ‘fill in the details’ is ideal. There was a good post about it not too long ago on here or on odforce by jeff I think… if I come across it I'll post it back here.

Ahh, great. Thanks for sharing. Interesting stuff for sure.

This is the old discussion - what do you needed to get realism out of Houdini?

The videocopilot Tuturial above is good example how fast and time saving you get realistic (!!!) Fire Explosion in other 3D Apps.

To get exact this result out of Houdini you need tons of hours, tons of renderpower and tons of knowledge which is was made in production ready quality in less than 50 Minutes in FumeFX.

The the volcano tutorial: (https://vimeo.com/44129053) [vimeo.com] shows 35 minutes inside HD - but NOT how you get the end result - voila here is the result. The difficult for realism begins after this tutorial.

Realism out of Houdini is possible for big Studios with the tons of ….

I'm not sure I'm following you Eagle66 on this!
You're not building up any constructive arguments in your post…

What you see in the “videocopilot Tutorial” is easily reproducible in Houdini… and I can assure you that you don't need tons of Hours and a big production company with the “Tons of….”

I've worked with MAX and FFX for many shots, and if you don't know MAX and Thinking particles or pflow and FFX… your going to end up with tons of hours trying to figure out how to make this!!

Have you tried the shelf tool in Houdini?? you know that you need any object and with one click on the shelf tool (without no tweaking) you're going to end up with something pretty similar!

that's why I'm not sure where you are waisting those tons of hours!

lari

One Click - thats sound funny. I have watched a 10 hours Houdini Fire Class on fxphd with hours of Node based Shader tweaking in hundreds of theoretical parameters and the results aren't not half of the quality from this video above.

This results helps also not really:
I
http://vimeo.com/44619541 [vimeo.com]
II
http://vimeo.com/44619540 [vimeo.com]

larikaram
Have you tried the shelf tool in Houdini?? you know that you need any object and with one click on the shelf tool (without no tweaking) you're going to end up with something pretty similar!

Thats sounds interesting - are there any Screenshots oder Videos from this result?

Thanks!

Hmmm maybe Houdini is not one click solution, but with shelf setup you can do nice simulations.

1. Add sphere
2. Fracture
3. RBD sim
4. Use rbd sim as source
5. Pyro Explosion preset
6. Tweak source, like add curl vel…
7. Tweak shader
8. Render, PBR with ENV light
This is what i did here
https://vimeo.com/53774979 [vimeo.com]

I think resault is more less ok.

CeeGee
Hmmm maybe Houdini is not one click solution, but with shelf setup you can do nice simulations.

1. Add sphere
2. Fracture
3. RBD sim
4. Use rbd sim as source
5. Pyro Explosion preset
6. Tweak source, like add curl vel…
7. Tweak shader
8. Render, PBR with ENV light
This is what i did here
https://vimeo.com/53774979 [vimeo.com]

I think resault is more less ok.

Wow, that is pro!

How long do you think it took you too do? minus the rendering time.

How do you render out the pyro RGB lighting pass?

Being a somewhat noob at Houdini, would you point me in the right direction to be able to achieve results like that?

Hey there again,
Ok so here is a scene that I've put for you with some renders. Check it out and let me know if you have any questions!

My steps:
1- Add a sphere
2- Click Explosion Pyro shelf tool
3- Added a Sky light shelf tool
4- Tweaked (in the shader) the colors of the Smoke and Fire
5- Tweaked (in the shader) the density amplitude of the Smoke and Fire
6- Added the new Volume Light in 12.5
7- Rendered

I shouldn't have used the term on click but for sure you can see that you don't need that much to get a good result!
And If you take your time to tweak Pyro and the shader then you can achieve great renders!

lari

Lari! I can't express enough thanks for this, I'm going to look this over like crazy. I hope you don't mind if I come back with questions

No problem, I'm glad to help.
What I would recommend you is have a look at the file, play around with the variables and see how pyro reacts (You might want to lower the Division Size of your fluid box).
But I strongly recommend you to go through the many good tutorials on the sidefx.com or even on vimeo. They will give you a strong in depth knowledge on who different variables (heat, temperature, fuel … ) affects the simulation.

enjoy!
lari

Thanks a bunch for the advice! The Houdini hip file has already helped me a lot!

Hi hereacoon,

larikaram scene is realy great, you can learn a lot, for AOV you can read what AOV you have on pyro shader and use that in mantra render, and for RGB, this is simple setup using RGB lights, and for fire i used ramp with RGB color. On internet therre is a lot of setups like this for fume.

Play with this scene, try to play with source, tweak some parametars, run tests, compare….

Houdini 12 Pyro - Shape Settings Wedge Tests
https://vimeo.com/49552856 [vimeo.com]

Houdini 12 Pyro - Shape Settings Tests
https://vimeo.com/61705851 [vimeo.com]

Settings Comparison in Houdini Pyro
https://vimeo.com/36851295 [vimeo.com]

Okay many thanks to larikaram and CeeGee - I will try it again.

It seems I have something wrong, I have simulation and rendertimes about 1 Hour per Frame with Pyro shelf tools on a Intel Core i7, so I abort….

Can you share your scene?

I am also using i7 950 3.05ghz - 24 gb ram.

Igor

Thanks a lot for the videos Cee Gee, I'll look into this.