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## Popular Content

Showing most liked content on 07/20/2018 in all areas

1. 2 points

## radiating normals for curve having concave and convex shape

enable [x] tangent Attribute tangentu in node "resample2" You can store the cross product in @N if you want, but by doing @N / @tangentu / @tangentv , you have a normal, orthogonal frame for each point, which is a strong foundation for anything downstream IMO. Also see polyframe, which generates N, tangentu and tangentv. No need to do cross products by yourself
2. 1 point

## Parametric and Procedural Design with Houdini (Houdini Tutorial FB page)

I've recently started using Houdini coming from a Grasshopper/Rhinoceros + Architectural background and quickly I realized it's such a great tool for parametric & procedural design for modeling some geometrical shapes which sometimes GH is not good at. I'm planning to post tutorials for Houdini to following Facebook page and Youtube channel as my note how to make geometries I'm interested in. [Facebook Page] https://www.facebook.com/ParametricProceduralHoudini/ [Youtube Playlist (Fast ver.)] [Youtube Playlist (Slow ver.)]
3. 1 point

## Houdini Pyro render issues

Hard to tell without more info, but usually : you can solve the « stairs » problem by increasing the substeps of your simulation. With small substeps, those stairs effect appear where the speed is high. I don’t what source you have used, but if it’s from particles or object, you can also increase the substeps, to smooth the emission and then avoid having those artifacts. The « boiling » : well, I think you’re talking about the smoke taking the form of a big smooth mushroom while getting high in the air ? You can limit this either by lowering the temperature of your your smoke, and/or decreasing the buoyancy of your pyro sim. The force that is applied to the smoke is buoyancy * (delta Temperature). A bit like an Archimede force but with difference of T between the fluid and its surrounding. By decreasing that, you limit the mushroom effect. Hope that helps
4. 1 point

## Jigsaw Puzzle

As if figuring out Houdini is not hard enough by itself.... HDA uploaded, use Show Blueprint while tweaking params...
5. 1 point

## use point attribs in volume

easiest way is to use point cloud functions in your shader to read the points and get the average Cd in a radius, then use that as your volume color. if you need the colors in SOPs, it's more or less the same thing... pcopen() and pcfilter() in a volume wrangle to get the average P within a radius, then bind that to a Cd vector volume. just have to create the volume in advance, before the wrangle.
6. 1 point

## POP Grains - Experiments and Issues!

try disabling Constraint Averaging and adjust your weights as Jeff describes in this master class around 32:50 https://www.sidefx.com/tutorials/h15-masterclass-grains/
7. 1 point

## Swirl Pyro Equivalent

I'm working on something related to art direct the swirly motion of gases; Its an implementation of a custom buoyancy model that let you art direct very easily the general swirly motion of gases without using masks, vorticles, temperature sourcing to have more swirly motion in specific zones, etc. Also it gets rid of the "Mushroom effect" for free with a basic turbulence setup. Here are some example previews. Some with normal motion, others with extreme parameters values to stress the pipeline. For the details is just a simple turbulence + a bit of disturbance in the vel field, nothing complex, because of this the sims are very fast (for constant sources: average voxel count 1.8 billions, vxl size 0.015, sim time 1h:40min (160 frames), for burst sources, vxl size 0.015, sim time 0h:28min). I'm working on a vimeo video to explain more this new buoyancy model that I'm working on. I hope you like it! Cheers, Alejandro constantSource_v004.mp4 constantSource_v002.mp4 burstSource_v004.mp4 constantSource_v001.mp4 burstSource_v002.mp4 burstSource_v003.mp4 burstSource_v001.mp4 constantSource_v003.mp4
8. 1 point

## Kohuei Nakama's Effect

Here is another slight variation. Instead of generating a fixed length line segment that moves through time, generate the full path over the entire time range. Then add a primitive attribute @path_pos to each line primitive. Drive the offset along path value, of the path deformer, with this attribute. Then you can have some geometry leading others as they each flow along their own path. float frame_end = 200.0; // deform_path node expects input in the range of 0-1. f@path_pos = fit01(@Frame,0,frame_end); // Now offset each path based upon it's index. float delta = 0.05; // per-line delay time can be set here. f@path_pos -= (delta * @prim); ap_ps_Cardume_Odforce_v3.04.hiplc
9. 1 point

## Divide object during RBD (copy to points) [SOLVED]

I used assemble SOP so that I need the number of pig primitive which have name attribute. Then I enable Fracture By Name of RBD Fractured Object SOP in DOPnet. test02.hipnc
10. 1 point

11. 1 point

## Make Curve In VEX

please take a look at the attached file. it´s an example how you could create bezier curves with arbitrary degree and another one relying on beziers in hermite form since you wrote about blending curves... petz curves_vex.hipnc
12. 1 point

## Make Curve In VEX

Put all point positions into an array and make parameter "t" slide e.g. from 0 to 1 inside a for loop. int steps = chi('steps'); vector all_points[]; resize(all_points, npoints(0)); for (int i = 0; i < npoints(0); i++){ all_points[i] = point(0, "P", i); } int prim = addprim(0, "polyline"); for(int i = 0; i < steps; i++){ float slide = i / float(steps - 1); vector pos = spline("catrom", slide, all_points); int inter_pt = addpoint(0, pos); addvertex(0, prim, inter_pt); } Also a simple function for interpolating 4 points to a curve by yourself would be: int steps = chi('steps'); vector pt0 = point(0, "P", 0); vector pt1 = point(0, "P", 1); vector pt2 = point(0, "P", 2); vector pt3 = point(0, "P", 3); int prim = addprim(0, "polyline"); for(int i = 0; i < steps; i++) { float slide = i / float(steps - 1); vector pos0 = lerp(pt0, pt1, slide); vector pos1 = lerp(pt2, pt3, slide); vector ipol = lerp(pos0, pos1, slide); int inter_pt = addpoint(0, ipol); addvertex(0, prim, inter_pt); } VEX_spline.hipnc
13. 1 point

## Realistic ice melting effect

Hi, I have a project where I want to create a realistic ice melting effect. I am quite new to FLIP fluids, however I read a lot and watched some masterclasses about how the solver works in Houdini. But I still struggle at a lot of areas. Reference for the effect: What I have done currently is played around with the viscosity. Basically I took my geometry and created points out of it, then I an SDF volume from the same geometry and passed attributes the values onto points. So, the inner most points would have the lowest value and going to the surface it would reach 0. I fitted those values from a range like 1,000,000 to 0 and then using a geometry vop in the dop context i just subtract some viscosity from the points at each time step. Here are my low resolution tests: Particles: Meshed: https://www.youtube.com/watch?v=IokJPFoNi5w&feature=youtu.be I got a somewhat decent result, however it looks more like ice cream melting than ice. It feels like the melting is not solid enough. The particles are not holding the shape as ice would. That's how far I got for now. I have a few more ideas, though (haven't tried it yet): 1) Instead of using viscosity I was thinking to start with all the points disabled (not solving) and then gradually activate them. 2) I wanted to try out using pressure, like in this example (they are using realflow): http://https://vimeo.com/13599797 but have no idea how to manipulate the pressure field: I was hoping maybe somebody with more experience would put me on a better track and maybe have more ideas or suggestions on what would be the best way to achieve this result. Also, maybe you have some suggestions on the shading part? I have some ideas, but I always tend to take the most complicated approaches I am using H15. Thank you in advance
14. 1 point