# Midasssilver

Members

114

1. ## Crowd Transition Help

I have am testing the transition between 2 clips in a crowd sim. I only have those 2 clips enabled, and I can see that they have a connection in the Transition Graph. The problem occurs when I queue the transition on a specific frame. Houdini is telling me that the frame Clip B is similar to Clip A is on frame 435, but I know that the frames don't match up until 438, and I can't work around it. If I try and set up a custom transition at 438, the transition is just skipped. Anyone know a way to either force the transition to happen at the appropriate frame, or tell my why Houdini is interpreting my clip incorrectly. Thanks!
2. ## Crowd Transitions not random

You ever make progress on this? Bump

I dont have the time to dip into your hip right now, but I will say this; you need the right velocities to create something like a tornado. Right now, it looks like you almost only have your source, you don't have smoke coming off the edges of the tornado all the way around. If you just emitted velocity outwards, you would get that, but then it would look nothing like a tornado, therefore you also need a force that pulls the smoke back in. So, if you have a twisting tube as your source, and it inherits velocity from the speed of that tube, it should shoot outwards. Then you can multiple that vector by a velocity field that pushes inwards, so that you get both the initial outwards push, and then the suck back in. When those forces are balanced correctly, you can get something that looks like your reference.
4. ## Hair initial state

You need to increase the stiffness parameters, and make sure you don't have too many points in your wires, or they will just fall down. The less points you have, the stiffer it will be, but you still need it to bend and sway with the head, and you still need gravity.
5. ## guiding ocean guiding ocean problem

What do you mean the ship sinks? It falls onto the surface, and then floats, but it needs to undulate under and over the surface, like its on water. I played your scene, and I didn't have any issues. As the boat reached the front of the container, the container followed it, which is what the guided ocean layer does. Also, I'd recommend either using a larger particle separation or adjusting your water level or flip container, because that was too high res of a sim for you to iterate on effectively.
6. ## Unexpected white color in my render

Id say, the main issue is that you don't have a material on your object. I tried rendering your object with different shaders, and a principled shader with a light reflection model gives you the same result. If you put a constant shader on the geometry, or if you remove the headlight, the white also disappears. It looks like mantra is interpreting your volume trails as poly wires, and the whites you are seeing is specular highlights from the headlight in your scene, which is why when you change to constant shading, they disappear. Hence, the importance of materials and lights when rendering
7. ## Rolling Clouds Simulation Using Smoke

Shouldn't be too hard. Just source smoke from points on a grid, (it looks like he used a disc), give them some initial velocity, add turbulence and some disturbance at the right time, a little bit of bouyancy and some gravity (or a high cooling rate) and you are done.
8. ## How to Export RBD sim from Houdini to Maya with out loosing Uvs?

This is just my guess, but do you have your uvs set before the RBD sim. If you don't have them on the geometry before the sim, they can get broken as they get simmed. If that doesn't work, upload a hip and ill check it out.
9. ## Anyone using .sim files?

The .sim files are written out on the cache tab of the dopnet. Enable Save Checkpoints and specify your checkpoint location with \$SF instead of \$FF as the incrementer. We use \$SF to stand for simulation frame. This will correspond with whatever the first frame of your simulation is, so be aware of that. Then change the checkpoint trail length to the length of the sim, so that the entire sim is accounted for. Next, make sure the checkpoint interval is set to 1, so that you get every frame taken care of. Now, when you play the simulation, you will automatically write out .sim files. Just be aware that if you suspend the simulation on a partial frame, your simulation will break. In that case you need to delete the last incomplete frame, ctrl+click the little brain icon, and your cache will re-set to the last complete frame.
10. ## How to export UV from Ocean Preview to Maya

The texture isn't tileable because when you bake all displacements to one layer, it is fit into a 0-1 uv tile, which isn't tileable. Wish I could help your second point, but it's been a while, and I got a little hung up there myself. Hopefully someone else can chime in.
11. ## How to shatter animated objects?

Unfortunately what you are trying to accomplish isn't as easy as that. You need to switch between animated and deforming shards. I'd check out this video:
12. ## Issue with trail sop velocities

Hey there, so I opened your hip, and a couple things I'd suggest. First, when posting about a problem, create an extremely simplified version of the problem and see if you can recreate it. That is what you should be uploading here, not your whole project file with millions of dependencies we don't have. We are most likely not going to re-build your hip, and if it has a cache as a dependency, it better be a simple one. Also, Id suggest leading people to the problem you are experiencing, within the hip file, with notes. Without that, people might just stumble around. No one wants to go on randomly looking for something that isn't easy to find. So try and re-create the problem in a simple scene, and re-post, and Ill def check it out for ya.
13. ## Issue with trail sop velocities

Post a hip plz
14. ## Flip level goes down

Conservation of volume is a classic issue for flip sims. Usually you counter that by reseeding enough particles to keep the divergence of the simulation at 0.
15. ## Double surface on meshing

Try changing the rebuild sdf parameter to NONE on the particle fluid surface node. You can also try to turn on limit refinement, and leave it at zero. Second, turn off rebuild sdf.
16. ## Anyone know good and safe Edge Detail way for rbd destruction ?

One thing you can do is add a lot of noise to the entire geometry of the fractured pieces, including the edges, then switch between the active shards and inactive shards, so that you keep the active shards that have the displacement, and the inactive ones that don't.
17. ## Offset the time in an FBX animation

You can just use a timeshift and key the frame numbers for the start and end of the range you want. If I were you, Id shift+click on the keyed parameter after and change the interpolation to linear, so that you have an accurate retime.
18. ## Distribute particles more evenly?

If you want to emit an even amount in every direction at the same time, you must source from all points on the surface, and not use a noise as the velocity field. If you make a velocity field out of the normal direction you get from a facet sop set to Post Compute Normal, then you will get an outwards direction. Right now, since you have noise as what is causing your velocity, there will be parts that naturally move around the object, as opposed to uniformly outwards from the center.
19. ## Ocean not the same of the sim

I believe it is because the way that works is it inherits velocity from the ocean spectrum, therefore the waves will never be one to one. You can try adding a single wave into a flat tank, and you will see the same thing. There will always be a difference between the visualization of the wave on the grid, and how high the actual wave gets. If someone else knows a better way to work around this, Id like to hear as well
20. ## Keeping RBD pieces from falling off

Made some changes. The soft constraints aren't getting you any thing. Increase the strength of the glue constraints, and I added some collision geometry on the sides of your RBD to keep things in place. Also, you are shooting yourself in the foot by having your text start that high up. Just let it start barely above the ground and just settle a bit. Scene01.04.hiplcScene01.04.hiplc
21. ## 25th Anniversary of Jeff (Old School) Wagner joining SideFX!

Thank you for everything that you do Jeff!!
22. ## HELP!! import vdb to houdini

I don't know about the tool you are describing, but .vdb files can be read with a file sop. Just drop a volume visualization and preview the appropriate fields, otherwise it will look like a box of smoke.
23. ## smoke trail render smoke trail render

I responded to your post on sidefx, but if you used the smoke trail tool, then you are gunna get a smoke sim. Your picture would be a pyro sim.
24. ## smoke Plane Smoke Trail

Ok, now that you cleaned up your file and I can see what you were intending to do, I can give you advice. First, definitely go with a dop simulation. The method you ended up choosing for your smoke was simply converting a particle sim to a volume and rendering it. Because that method completely relies on your construction of the particle sim, it will never look really organic, which is why your best option is to source smoke from something like a disc (think chimney smoke), and make that your trail. Then, you need to work on the control field parameters of the turbulence to get the swirls happening to the smoke at the right time. Look at some reference (even pictures will do), to show you the type of shape you are looking for. Videos will tell you the speed of the swirls you want to get. You can get this working in a simple scene, then parent it onto the location of where the jet-stream should be emitted from, so you don't need to worry about a moving source.
25. ## Houdini pyro particles explosion

If I were you, I'd start experimenting with shelf tools and see how they work. You need to know about the separate parts that go into a simulation, and that's a great way to start. Create a sphere and click on the explosion tool. Look at how fuel and temperature source volumes are created. Once you get a handle on what creates an explosion, then to get the tendrils, you need fuel in the shape of the tendrils to exist. You can do that with a pop sim, but that's still pretty far ahead of where you are at.
×
• Donations