Hi,
I do a house geometry. The raw house is a box (mesh) with blasted holes for the windows. I did one window with curves/sweeps/skins. Then I distribute the windows with the duplicate function. Unfortunatly the holes are not complete symetric. As long as I do the duplicate in a symetric group, everything is allright. But when I have to start a new group, the original Window, where I append the duplicate sop, is allways in that group and then transformed as the duplicated instance. For my purposes I would like to append a duplicate sop to the original, and then would like to append more duplicate sops to that instance, but they should not contain the original window. … Procedurally thinking, I dont know how to avoid this, because the original is always in the chain of operators.

Hmm. Complicated to explain. e.g. you have the left upper window on the front of the house in a row as the original. With duplicate I can complete the complete row as long as the distance between the windows is the same. Now it goes to the right side of the house. I do another duplicate operation, rotate the window by 90 degrees and move it to the upper left position on the right side of the house. From that instance I would like to do a duplicate, that can fill up the complete upper row on the right side. But in this case, the unrotated, and unmoved original instance is inside the first duplicate, and will unneccessarily be duplicated and distributed the same way as the first rotated and moved duplicate. I would like to append a dup sop, that will only take the rotated and placed instance in account, but will ignore the original from where its coming.

How do you manage this problem?
greeting,
- Frankie

PS I am new to houdini and I do my first project. With the help of ‘magic of houdini’ and several video tutorials I solved a lot of problems until now. But some questions are left, where I cant find the answer at the moment.

Hi Frankie,

It's complicated to read too. Instead of a Duplicate SOP, you can use a Transform SOP instead and then merge to results together. This is from what I can gather from the post.

The best is to post an example hip file so we know what you're trying to do.

Cheers!
steven

Thanks for your help Steven,
and yes, you are right. Here is a light modified hipnc file that shows my problem.

If you open it, and jump into the PathBuilding Object (sorry some nodes inside are labeld german, but they are not interesting) you see a more or less big network. I am talking about the windows and the duplicate problem. In the network you find the interesting example duplicate nodes on the most left side. The window geometry with the original window is a bit above.
The original window is placed as the upper left window on the front of the building. Now I triy to fill up all windows from that object.

When you open the example file, the problem duplicate nodes are bypassed.
You see the most left duplicate 1 node (FirstRowThreeWin). That makes to duplicates into the right direction. This is okay.
Next, the next window to the right is made with the duplicate 2 node. I cant make it with the first node, because it is a bit more forward than the other three windows. This window is okay.
And last, I made upper left Window on the left side of the building with the duplicate 4 node. This one is rotated -90 degrees (and moved), because it is on the side. This one is okay.

The Problem nodes are the appended nodes as I described in my original posting.
Click away the bypass flag on the duplicate 3 node. You see, that now there is on more window in the middle part of the building. If you looked very exactly to the building, you could have seen the problem. To make it better visible, click on the bypass node of the duplicate 1 node. Now you see, that from the left, there is a second window in the first row, that should not be there (because that was already created by duplicate node 1). What I wanted was, that the duplicate 3 node only takes the window, that was created by node 2, and make _one_ more duplicate to the right. But it made a transformed duplicate of the original, too. That was unwanted.

With the second example, this problem becomes more obvious. Click away the bypass flag on duplicate 5 node. These are the nodes for the windows on the left side of the building. When you clicked it away, you see that a second window appears on the left side, which is okay. But also the there is now an instance of the original window transformed outside the building! Same effect as with node 2 and three, but more obvious a problem.

The question is now, is it possible to append a duplicate node, to another duplicate node, that only duplicates the duplicate of the parent node, but not the original?

I hope this now more understandable (obviously not without looking at the file ;-)


greetings,
- Frankie

Hi Frankie,

nice house! I played around with your file a bit and used a slightly different approach by using the copy sop.

I grouped the left most point of all your window cuts, grouped the points in subgroups for every facade, made normals pointing outward of the facade and then copied your window on the points. I added added two transform sops to your window geometry, one to rotate it so it would align properly with the normals.

Now the other transform is a bit crude but what it is supposed to do is to put the point of the window that is going to be copied on the window cut points to the origin (0,0,0). I couldn't make this out from your network (being to lazy to dive in deep). If you now which point it is you could add a point expression to this transform sop so that that point is at (0,0,0).

I also added a duplicate network which gives more or less an answer to your question. By using groups you can control the parts of the duplicates you want to duplicate further.

Cheers,
Hans