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Everything posted by Andrea

  1. Pyro renders taking way too long

    This quality values are already low, seems like a lot of time. What I would check: - Is your pc usually that slow with other volumes rendering? - Which resolution are you rendering? - Which and how many lights do you have? Keep in mind that enviroment lights take longer to render than a directional or a point light for example - In the light settings I would check the Sampling Quality if is still at 1 - Being the smoke fairly transparent is possible that Mantra thinks is all noise and is shooting every time the Max Ray Samples. I would also try to reduce this to 4-5 if you have it at an high number and set higher the noise level, just to see if this is the problem
  2. Vellum jitters non-stop without loss of energy!

    I am sure is possible also with the SOP solver to filter the data using several timeshifts but with CHOPS is a lot faster to setup. For this kind of things often it can save a lot of time being just one node and one line of code
  3. Vellum jitters non-stop without loss of energy!

    Ok, a bit off topic I should have tried to do it with vellum but I had this idea. What about using chop as post-process for filtering the noise/jittering? Usually the jittering starts or at least is visible when the object is almost static. In this case you can use the length of velocity to blend the cloth/vellum object between the filtered/non-jittering simulation and the non filtered object. This way you get the best from the two. This trick saved me a lot of times (if you consider three a lot) and the supervisor was happy about the "clean sim" vellum_basics__jitter_02_chop.hip
  4. Tranfert information from color Pyro to geo

    You have this black spots because you are using the volumesample also on the heat, which has also values of zero. The zero heat values multiplied by this temperature ramp are causing the black spots. It depends what you want to achieve. You can modify the operations inside your volumeVOP or you can modify the heat before it goes inside the volumeVOP (clamping/fitting it to 0.5-1 for example)
  5. When To use compression For BGEO

    I have never thought too much about it but I have used both of them. Useless to say I almost never had problems with both of them. The only thing you may notice is a little difference with the compressed format, which is faster in loading/writing the caches being smaller file sizes. I think is worth to mention that I had an issue just once using the compressed format and packed disk primitives. Something wasn't working correctly using compressed caches made in Windows and rendered in Linux machines. But I can't be 100% sure since at the time the farm was new and had several other issues. I just know that if I was using the non-compressed files I was able to render this instanced buildings but not with the compressed one. I have no experience with them
  6. An idea could be mix the texture values based on the geometry rest position. This should produce smooth values on the edges and help on the blending
  7. That's what I was searching for, thanks. Doesn't matter if it's not for Houdini There is the paper so probably I can adapt it somehow for the refraction.
  8. HI guys! Do you have any idea if is possible to fake the presence of an object in the refraction inside of a shader? I have a piece of glass and I would like to make it refract a grid (or better a texture) as it is below. The point of this is that I am trying to create a shader that always refract the user specified texture without the need from the artist to manually create a grid, set the uvs, position it to a certain height and apply a material with a texture. Ideally the result should be the same between the two options, without a big difference.
  9. Attach Flower head to simmed geometry.

    Understood, thank you!
  10. Houdini 18 Wishlist

    Rendering: - +1 for some sort of improvements for Mantra - Using the principled shader I don't like that much that the "Base color" influences the applied textures. In my opinion it shouldn't be a mix but the textures should override it. Others: - The possibility to modify the color of parameters label using a color palette. It would be easier to show which parameters are more important and need to be changed/have been changed - I have recently discovered the power of COPs but while Houdini is the most stable program I know, with COPs crashes quite often. - The possibility to decide in the preferences if, when we use the shelf tool, DOP networks or nodes are created in a new geometry node or inside the same SOP network. - Improvements on the general look of volumes simulations.
  11. Attach Flower head to simmed geometry.

    That's really smart Andrii! I have a couple of questions if you don't mind: - So the translate function is for apply the rotation matrix to the flower geometry right? Basically is an offset based on the point position - Why the qmultiply? What is going to return the multiplication of two quaternions?
  12. Attach Flower head to simmed geometry.

    Hi! I love this kind of stuff I have attached an example. I had just 5 minutes to do it so I couldn't test it properly but it should work. The idea is to use the normal of the attachment point between the flower and the stem and transfer the rotation from the stem to the flower. Basically you use the dihedral function to find the difference between the rotation of the flower in the rest position and the rotation of the simulated stem (I have use a trasform node to move it around). After you found it you transfer this rotation to the transform matrix of the flower which is packed. I packed it just because is easier but I guess you can do it also without packing. When I have some time I can explain it better if you need to Attach_Flowerhead_fix00.hiplc
  13. Rigids Sim

    This is happening because the number of "packed disk primitives" between the two branches that are going into the last point wrangle aren't equal. In the wrangle you are using for example: matrix3 transform = primintrinsic(1, "transform", @ptnum); This is assuming that the number of objects between the two inputs are the same. If not, is going to take the transform (rotation), pivot and position of the wrong paired piece. Your error is that you are starting to save the pieces in the node "filecache2" from the frame number 1, meanwhile it should start from the frame number 0. That's the reason why I like to use the function findattribval, which pairs the pieces by their name and not by their number.
  14. Convert Mesh to fluid that stays the same size

    If the geoemtry fits perfectly, it should keep the volume almost perfectly. Could it be that there is something wrong with the collision geometry? Maybe you can simulate it using a flat tank and after the simulation mesh the fluid as it's inside the bottle, of course if the bottle is not in movement but static.
  15. Agree, alternately you can delete the primitives which normals are pointing towards the middle of the geometry
  16. Rigids Sim

    Hi! If you mean the initial rotation that the pieces get from the metaball force is because you need to invert it. Put it to -800 for example and the pieces will fly outwards normally
  17. fore each loop question

    I have never tried so don't quote me on this but you should be able to do it. You can put down a "render node network" inside of your HDA and then create the wedge node inside of this one. This way you will carry the wedge setup with your digital asset
  18. fore each loop question

    Usually in this cases the wedge ROP is the way to go. Without a foreach loop, you need first to delete all the pieces except for the one that you are iterating on and then save it to disk. The wedge ROP will help you to do this for each piece
  19. My Effects Pipeline

    Very cool stuff! Congratulations! How long have you been working on these?
  20. flip points id vs ptnum

    Yes that's right. Sorry I misunderstood the question
  21. flip points id vs ptnum

    You can add ids for the points also in the flip simulations. It's just an option disabled by default in the behaviour tab of the flip solver. Turn it on and you will have the ids
  22. Fur and snow (+hip)

    Hi everyone! The past week I worked on a personal project for learn something about hairs - vellum. It's my first project ever with hairs so I guess is nothing special but several people asked to see the hip file so here it is. Final result: Hip file (I had to recreate it but it should be pretty much the same): groom_clumping_03.hipnc
  23. All the previous advices are valuable. I would just add that it could be a nice idea to generate through particles/geometry a field to use as threshold for guide your simulation. As kleer said pyro is difficult, that's because there are a lot of values which are all related to each other. You change one of the fields or parameters and you will have a completely different look. The result of course is not random. You can know really well what each parameter does, but is not that easy to have a specific idea of what will be the result will all the values/variables combined. I don't have much experience in Houdini and FX in general as some people here in the forum, but I think that they can confirm that. That's why, when is possible, is not a bad idea to reduce this "randomness". For example you can create some particles, get the aspect you prefer for the core of the flamethrower and then convert them to a density/vel/temperature field (your choice). Then you can import this field to the pyro DOP and set this as threshold for your flamethrower. If the current voxel is inside the threshold field, is going to follow the velocity field you generated previously from the particles. If is outside of that, it will obey to the current pyro network rules. See for example the particles I have used to control my sim around 00:10 in the video below
  24. Optimize Pyro Container, H17

    Thanks for the explanation on how to fix the vel problem Mechanica. I think that, at least for now, the best option is to convert the animation of an object to follow one axis and after the simulation rotate everything back. Sadly it's not always possible. I wish this could be a lot simpler. For example just create a box in SOP, rotate it how you prefer and use this as bounding box.