Hi, I am using wrangle SOP and I am wondering how I can get the values from a ramp into the code in order to use it?

Is it possible to export acceleration from DOPs? I know that there are alternatives like using Slope CHOP to get acceleration but I was wondering if you can get it in pops, maybe is possible in dops.

i have to export my particles for houdini with pdc to maya but in maya you can set only one attribute for rotation and you can select radians or degrees, you can use normals and works fine but what I have in houdini is both normal and up vectors to get the proper orientation when I am doing instancing inside Houdini, how can combine these two vectors to a single one in order to be used from pdc plugin inside maya?

i have to export my particles for houdini with pdc to maya but in maya you can set only one attribute for rotation and you can select radians or degrees.

You can use normals and works fine but what I have in houdini is both normal and up vectors to get the proper orientation when I am doing instancing inside Houdini, how can combine these two vectors to a single one in order to be used from pdc plugin inside maya?

i have to export my particles for houdini with pdc to maya but in maya you can set only one attribute for rotation and you can select radians or degrees, you can use normals and works fine but what I have in houdini is both normal and up vectors to get the proper orientation when I am doing instancing inside Houdini, how can combine these two vectors to a single one in order to be used from pdc plugin inside maya?

here is the hip


regarding my question for the up vector with normal vector… I gave the answer myself, it was a stupid question. I am getting close with vops but still missing few bits.

I havent done CHOPS before but this seam clear enough, the problem is that with one object or point which has few keyframes will be propably fast. I am thinking that with 100s of points coming from a particles sim, which means every frame there is an in point of animation in CHOPs will be slow. But even if thats not the case and I get the up vector from CHOPs as an attribute attached to the original points, how I will use it in combination with velocity's direction to rotate each instance object attached the points?

I will create a simple hip and post it soon

KMcNamara thanks for the reply, velocity gives me the main orientation but there secondary rotation in an helicopter based on its acceleration, when goes faster is leaning forward on x axis, when its changes direction by making a turn leaning sideways on z axis based on which direction . Maybe I can use an up vector but how I will combine the up vector with the N which gives me the main orientation?

I have a flock of helicopters using particles, how can I simulate the helicopter-like orientation based on their velocity/acceleration? Either during the POP-sim or post-sim inside SOP level. So far, I am using their velocity direction as N to have them facing forward. Is there any way to rotate points in VOPs?

anyone? intersting…..

I have a levelset setup using SDF where blends the geometry of two objects where there is an intersection. But when you animate one of the objects then there is a noise as you play the animation in real time. How can I reduce that?

I have attached hip.

cheers

Infernalspawn is closer to the latter. I have a geometry and i want scatter a number of points and as you said, distribute the best RANDOM pscale on to these points to minimize the gaps. The number of points are not that important, can be few less or more. This is the effect I am after

cheers

hello, I am trying to have a procedural animation of a bottle spinning horizontal along its y axis. I have a hip attached to demonstrate that.

As you can see inside the hip I have a point where its normal vector is in a spiral motion and I copy a tube to that point and everything works fine. Also it will calculate the distance of the ground based on the angle of the bottle but what is missing is the actual rotation of the tube in his y axis which should be based on the angle of the point's normal. Any idea?

I am afraid it wasn't what I had in mind. I want to give a number of points and a gap and the vopsop be able to distribute the pscale the available area to all the points randomly, in order to use the maximun possible space taking in count all the above variables.

In your fhip file the sum of the area is 10000 and the pscale sum of 500 points is 60. The goal is not to only to be 60 < 10000 but also as close as possible to that. The gap was 0.

thanks for the reply @tampte, I did already the latter using “AttrCopy” as there was no animation on position just on some attributes.

Is there any straight forward way to sent the points of a geometry into pops and keep the geometry after pops?

I have a surface where points have been scattered uniformly and I would like to distribute the pscale in a random function but the sum of them will not overcome the area of the surface including a gap between them.

(pscale_sum + gap) <= area_sum

Any ideas?

thanks for all the replies but I fixed it! Actually I got two way to fix the problem, the first is 80% fix, the second 100% but I think it worth to mention both for future reference.

The first solution I found, while I was observing the Details View, is that you could use a Mix between Goal Vector (Point Cloud Position-Current Position) and Tangent Vector from curve's normals. The bias of the Mix will be controlled by the length of the Goal Vector which goes through a Fit Range and the only parameter you have to set manually is the Source Max of the Fit Range with the max distance from the goal that you want the current particle to have until start mixing the Tangent Vector with the Goal Vector. This method will fix most of the problem but is not perfect in areas where the path curve changes rapidly direction.

The other solution is much simpler and 100% accurate. In theory you could use just the Goal Vector (Point Cloud Position-Current Position) as your velocity but soon you will realize that the particle moves from the emitting point to the first point of the path curve and stays there, that's because the Point Cloud Open while looking for the closest point in relation to the current position, it will always giving you the position of the first point of the curve. One solution is to create an attribute, which I named “goal”, for each point of the curve at the SOP level before the POPs where each point holds the position of the next point. Then inside you VOP POP, instead subtracting the P vector of the point cloud with the P vector of the particle, you will subtract the Goal vector from the point cloud.

In both method I use a normalize (to keep a constant speed) and an overall multiplier before I pass the Goal Vector to the velocity output. After the overall mult you can use other multiplier driven by an attribute in order to have a variation in your speed.

cheers,
Christos

P.S. in the second method the Goal vector attribute for the last point will not work because there is no next point but you can easily use a Two Way Switch where you can force goal vector for the last point to be 0,0,0.

instead of using particles i'd use a carve sop and a copy sop,
each copy itteration = 1 particle. that way it will always be on the curve

Thanks for the reply Seb, but I cant do that because I am using later another attribute to multiply the speed of the moving based on the surface where the path/curve is attached with raySOP. I tried to do this effect in sops, including the carve approach but it can be procedural this way, I have to keyframe the speed because it is depending on $F in order to keep moving.

I think it has to be a simulation and particles seems the right way to go. This thread is actually related to my previous one: http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=28850 [sidefx.com] where you can find another attached hip which is using the carveSOP.

Hi, I want particle(s) to moving along a curve but always be on the curve without any offset. I have a setup where a curve have tangent vectors on its normals using sortSOP and pointSOP and inside the popnetwork I am using as source of particles the first point of the curve/path and with a VOP POP I am getting the normals from the curve using pcopen and pcfilter, normalize and passing this to the velocity of the particles. The particles are moving along the curve but sometimes there is an offset as in this example hip I have attached.

How to make it follow perfectly the curve?