Hey everyone!

I've seen some old posts on this issue, but never found a solution.

I was wondering if anyone know if it's possible to clear all cache without having to close down Houdini.
The “Cache Manager” is only able to clear so much, and some cache is still left behind eventually causing Houdini to freeze. I'm currently working on a large terrain field, and I'm having to re-start Houdini after caching geometry to disk every so often.

If not, could I create a python script that will close and re-open houdini whenever I need to? Otherwise generating this terrain will become a very manual process, that I am sure I could automize.

Any help is much appreciated!

Audun

Hey Rob!

I have done some testing and yeah. I think I've been overcomplicating it.
Here is a test I did yesterday.

This is sourced used particles, but I'm going to do an RBD sim instead so I can get more variation in size, while having more interesting shapes. And then use particles to add more grains in some areas.

It's getting there, but still loads to do!

All the best,

Audun

Hey Diego!

Thanks for your reply! Would you have any tips on how I could get that “dissolving” look? That is why I've not tried RBD yet, as the chunks would be solid through the entire sequence. Unless I simulate the dissolving fx separately.

What I will try next is simulating RBD chunks, and then turning them into particles through a volume. Maybe I can do some cool dissolving effects like that.

Time to go back to the drawing board! Thanks for sharing your thoughts though.

If anyone have any cool tricks to cluster particles, so that they are nice chunks, throw me a bone. I've tried Pop Grains, but it's unnecessarily slow.

All the best!

Audun

Hey guys!

I've been trying to figure out how to do a simulation similar to this: (AT 0.44)
https://youtu.be/7WWJEJ9o0MA?t=44s [youtu.be]

What I am looking for is particles sticking togheter, but “dissolving” as they progress over time. Kind of how flour would react if punched. I have set up several tests where particles emit smoke. I hope to do a combination of a particle simulation and a pyro simulation, where the particles are emitting as they flow to create trails.

Here are some other good references to what I am refering to:
http://dearphotography.com/ImageLibrary/Kristian-Schuller/950/auto/Powder-Explosion-img.jpg [dearphotography.com]

http://media.gettyimages.com/photos/dust-explosion-picture-id158892924 [media.gettyimages.com]

http://www.850businessmagazine.com/images/cache/cache_8/cache_c/cache_4/shutterstock_141735493-937a34c8.jpeg?ver=1453460206&aspectratio=1 [850businessmagazine.com]

I have made a very basic particle simulation where I use several simulations, but I am non the wiser to how to achieve this realistically.

Do you guys have any tips to what I can try? I have attached my .hip file if you fancy a look. It's very rough at the moment.

All the best,

Audun

Yeah good point!

I am having really strange results still, but I think that is an issue somewhere else.
Thanks for the reply I like the idea of actual deforming geo aswell.

Hi folks!

I am working on a fluid morph simulation and need to animate the sopscalarfield VOP
in order to sim the fluids inside a moving volume.

The setup I am currently using is really simple, it creates a volume and imports it into the flip sim using the sopscalarfield vop, then applying a negative force inside a fieldforce vop.

The problem I am having is that I am unable to get the sopscalarfield to use the transformation data I have created in SOP. I have tried several different methods to import the transformation values into the Position attribute. I feel like I am really close to a solution.

I have attached a simplified hip file.

Any help is really appreciated!

Sincerely,

Audun


EDIT:
Funny enough I was only a few changes from solving the problem. I added a position VOP into the secound input of the fieldforce VOP. Now I can reference that to the animated geo.

Turns out sl0throp was right! I had a closer look on managing colours inside After Effects. Interestingly enough I've never had the need to until now!

Thanks for your help folks!

I would think this is an issue with the alpha map. I am using the .exr file format. I get the same problem with other file types. Pretty sure this is not an issue with Gamma, as I am using linear workflow.

I'm guessing alpha, but if anyone have any ideas I would love to hear them

So,
I know this problem has been discussed here before but I can't find the thread anywhere. Been looking for about an hour now!

The problem is that the render in Houdini looks different in After Effects / Nuke etc. In Houdini (on the top) the fire appears more orange and energic. But in After effects (on the bottom) it seems like there is something wrong with the alpha of the render. The values are weakened by something.

I'm sorry I know this has been discussed before, but I cant find it.

If you know the post I am refering to, or know what causes this that would be a great help! I'm very new to the Mantra renderer

Thanks!

I think you might be right! Now that I think of it it sounds like a good thing to try. At first I thought that maybe the sharpness on the Pyro was too high or that it had some kind of disturbance setting I had forgot about.

Thanks for replying though! I'll post the results later for good measure

What I find most useful with using Vray and Houdini is that Vray 3 comes with a VolumeGrid feature that you can easily export your FX from Houdini using the .VDB file format. I do not know if this is good to use for water, but I do know that you normally export water to a mesh which you can render in Max.

I am not sure about Max, but from Maya I use the alembic file format to export geometry, then do the effect in Houdini, and back to Maya again. I don't think Max is that much different.

I hope my limited knowledge of Houdini was useful in any way

Hey fellow Houdini people!

I just had a quick question regarding a strange artefact in my Pyro Flame simulation. The volume appears to be cut in pieces in some places. It may just be me missing a detail somewhere so I thought I would ask someone who might have seen this before!

as you can see on the picture it is chopped up and this also affects the render itself. Any ideas? Is this just a matter of resolution?

Thank you for having a look!

Hi folks!
First post here.

So I've been trying to learn the ins and outs of Houdini recently and I am working on a shot of a tank shooting. The goal is to master different pyro scenarios combined with destruction. My question now however is how would I go about spawning smoke based of the movement of the tank?

What I am guessing is to calculate the velocity of the tank. And when that velocity reaches a certain value, spawn smoke.

I usually never post on forums, because I like to find out how to do it using other means. The issue is that since I've not used Houdini that much yet, knowing what to search for is a bit tricky.

Any guidance is much appreciated!