I tried all of the tricks that were passed around in the other forums like adding extra params around dicing and pumping up sampling and shadow resolutions with out luck.

The two params that did the trick in eliminating those nasty 2 bit square wave shadows was increasing the Shadow Quality and Shadow Softness options in the light that is casting the Depth Map Shadows.

Additionally, after testing different angles, I noticed that the edges of shadows cast from peaks were getting choppy and bumping up the Pixel Samples in the Depth Map options in the lights smoothed it all out nicely.

Feels so good to start getting traction with rendering!!

P.S. The fixed HIP is attached.

Thanks for the quick and detailed reply!

The displacement bound param fixed the missing poly problems, and I'm sure your other thread and mucking around will reveal why those square shaped shadows are appearing on such a flat surface.

This is the first time I have tried using displacement maps and am getting odd errors that mantra or lighting changes don't seem to fix.

The errors are chunky shadows and black triangular missing regions from the surface. To see what I'm seeing, look at the attached image.

It's a simple scenario, but I attached the hip file is attached as well.

I found an older post about the problem that mentioned tweaking params in mantra, but H9 removed or moved those params.

Any one else run into this problem?

Good to know, I've never even used it :?

Thanks for the tip Simon, it works!

It's good to know that this can be solved with the Divide SOP, because I run into this problem with operations outside a Cookie SOP.

Attached are the the two approaches you outlined.

After looking at it further, your right SYmek. Sorting by vertex would work on a single line like I want, but the error I am experiencing is caused by multiple primitives making up what looks like a single line.

Now, I feel like a shmuck going on and on about finding the next point on a line. I'm also stumped at how to deal with these types of errors produced by a Cookie SOP (see error example attached).

I guess the burning question is…
Does Houdini provide a way to tell if two points are connected by an edge?

If this is possible, the we could use a method like yours andrewlowell to find the next point and store it in an array to prevent it from being looked up again…thus finding the true next point regardless of it's point number or position.

It's really neat to see the way you used CHOPs to do all that. I never thought of using it that way. Very creative.

Just like the expression nearpoint(), it works for finding the nearest point in space. I can't get it to find the next point on the line though. …which is what I'm trying to do. Does it do that?

Wow, nice file! Thanks for showing me how to do it in VEX. I've yet to learn VEX, so it's extra helpful.

I did some more digging around and figured out how to do it. In the attachment are three ways to use an image to displace points in geometry.

Using the texture on the geometry:
1. Use UV Project to texture geometry.
2. Use a Point SOP to color the points with the pic function: pic(“../cop2net1/OUT”, $MAPU, $MAPV, D_CR)
3. Use a Point SOP to displace the points using color values.
Note: This method is very effective, since your free to displace points on any shape no matter how non-uniform it is.

Using COPs and pic function
1. Load image into COPs.
2. Use a Point SOP to displace points with the pic function:
pic(“../cop2net1/OUT”, $BBX, $BBY, D_CR)
Note: This method is restricted to a perfect grid.

Using COPs to CHOPs to chopi funciton:
1. Load image in to COPs.
2. Use Image CHOP to access image data.
3. Use Point SOP to displace points using chopi funciton:
chopi(
“../chopnet1/OUT/r”+
floor(
fit(
floor($PT/100), 0, 100, 0, chopn(“../chopnet1/OUT”)
)
)
,
floor(
fit(
$PT%100, 0, 100, 0, chopl(“../chopnet1/OUT”)
)
)
)
Note: This method is also restricted to a perfect grid.

I have geometry with a texture on it and want to use the color values from the texture to displace the points on the geometry.

I can't seem to access the color of the texture using the Point SOP. Is this sort of thing possible?

Sorting by vertex using the Sort SOP doesn't work. It reorders the points, but not in the expected way. See the attached example.

I have a jagged line with oddly ordered points, that Sort SOP is incapable of fixing.

Is there an expression or some method to start with one end of the line and find each next point?

Since the line is jagged, using nearpoint() finds points that are not the next one along the edge.

I can see the points connected by edges, but can't seem to find any info on how to use what I see.

Any one else run into this problem and find a way around it??

I can't find any information on how to actually reference an incoming group in VEX. I then want to manipulate points in that group.

I have a group of points going into the input of a VEX SOP. Any ideas?

If the point group was an array, in another language, I would access it like this:
group1.x

After digging around on the forums, I ran into a way to procedurally select edges and then PolyBevel them. Check out the attached hip, it works pretty well.

The process I used goes something like this:
> Group: Select primitives to bevel
>> Crease: To use group of prims, change Operation to “Set”). Or just keep all settings at default if you have no groups.
>>> Subdivide: Turn on “Generate Resulting Creases”
>>>> PolyBevel: use group “creases” made from Subdivide

The big downsides to this approach is when using points to select nearest primitives. The result bevels all sides of connecting primitives versus, just the point path that you may have wanted.

Unless I'm missing something, it would be very very nice to see extensive edge support built into the Group SOP.

I know this is an ancient post, but the problem of procedurally dealing with edges is still a pain. Or am I missing something?

After a lot of poking around, I have realized that Houdini's cloth DOPs can not handle complex sims. I am now looking into http://www.syflex.biz [syflex.biz] and for the time being just going to hand animate the cloth.

In order to get a cloth like motion while hand animating points, I was advised to use this method.
1. Make keys points
2. Animation the points roughly.
3. Pull the points into CHOPs with the geometry CHOP
4. Add a spring CHOP
5. Use other CHOP filters if needed.
6. Pull points back into SOPs. Using channel SOP.
7. Skin surface.

The file consists of a dome attached to a ring (each made of cloth) both of which sit on top of a large sphere (static rbd) with the same diameter. The sphere is there so the dome and ring keep there general position and shape.

The dome also has a cut from the center to it's edge. The cut and the outer perimeter of the dome are stitched together with constraints that break when enough force is applied.

The ultimate effect is to use a moving constraint to peel away the dome. So it looks like thin tissue ripping from the cut and then the outer perimeter. The problems I am having is just getting it to exist without any of that animation.

In the DOP network you will notice two red DOP constraints. One of them moves and one does not. The one that moves is the test to see the dome being torn away from itself and the perimeter. When either of these are turned on, it causes even more problems.

I still haven't figured out where all my errors are coming from, so I attached the file I'm working on. Hopefully it can glean some light on the specific errors I am having.

I'm running out of time to get this project done, so any insight into this problem would be greatly appreciated.

Thanks,

I've been trying to figure out a way to use a cloth constraint multiple times within DOPs. Within SOPs this is easy to do with a ForEach SOP, but I can't seam to find the equivalent within DOPs.

I know there must be a way, especially with seam DOPs that can handle creating seams of constraints with any number of points in the group inputs.

Maybe I missing something obvious.