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cyclinggimpe
I have been fiddling with Houdini for a week now and have a question about copying objects. After creating the object in Objects level and then create a sphere in the SOP's level, I would go back to Objects level and then hit tab > copy and select the object and right click and I would be able to copy it. But, when I am in the SOP's level and want to copy the sphere, Houdini would ask something about a template and after right clicking a couple of times a transform handle shows up in the view. When I move it, there isn't a second sphere in the view, just the handles. But, I was able to hit Tab > Duplicate in the SOP's view and was able to make the copy. What am I doing wrong with the copy command?
stevenong
Hi there,

You did not do anything wrong. The Copy & Duplicate SOP works slightly differently.

With the Duplicate SOP, the “Number of Copies” parameter refers to how many duplicate copies you want while the Copy SOP's refers to the total number of copies you want.

So for the Duplicate SOP, specifying a value of 2 will yield three spheres while the Copy SOP will yield only two spheres.

I hope the above helps!

Cheers!
steven
cyclinggimpe
Thanks for the reply.

I think I may not have explained myself well enough. I couldn't get the copy to work correctly in the SOP's level for some reason. I'll go back into Houdini and try copying a sphere in the SOP's level again and write out everything I did and the results.

Edit: Okay, I tried out the copies again and wrote down what I did. Here goes.

1. Objects level - created geometry and named it test1.

2. Went into SOP's level and deleted the file1. Created a sphere, made it a nurbs and scaled it down. I hit Esc (to go to view state). Then I hit Tab > Copy. Houdini asks “Select the geometry to copy and right-click to complete”. The sphere is selected, so I right-click. Houdini then asks “Now select the template geometry, if any and right-click to complete”. I don't know what the template geometry is for, so I right click and nothing seems to happen; so, I right-click again and there is a copy in the network editor with the display flag and render flag on. But, in the view I only see the manipulator handles. Also, in the network editor, the input connector for the copy1 Op is divided into 2 and it is parented to the original sphere1 on the left side of the input connector. This one didn't seem to work.

But when I create sphere in SOP's and then go to the network editor and select the new sphere OP, do a ctrl-c and then ctrl-v in the network editor, I get a second sphere (but only can display one at a time until I connect them both to a Merge Op and then I see 2). This copy method works.

I then tried to copy the sphere from the view (in SOP's) again using Tab > copy and then noticed that I had “Number of Copies” set to one. When I set it to 2, the second sphere showed up; but, I had to keep it parented to the original or else I would get these errors: “No Geometry Available” and Not enough sources specified". I don't know why it's different this way. There must be times that each method would be used.

I read the copy section in the Geometry pdf file but didn't get very much out of it.
stevenong
Hi there,

It seems like you are confused with the Copy operation for Objects & the Copy SOP.

If you use the Copy operation for Objects, it behaves like Ctrl-C & Ctrl-V.

However, for the Copy SOP, you are making copies of the input geometry & not the SOP you selected in the viewport. To copy the Sphere SOP so that you have two Sphere SOPs, you use Ctrl-C & Ctrl-V.

Please try this: After completing the Copy Operation by selecting the Sphere SOP & right-clicking twice, you get a handle right? Now, increase the number of copies to 5 & drag the handle around.

Hours of joy with the Copy SOP!

I hope I have not confused you further.

Cheers!
steven
stevenong
Hi all,

2. Went into SOP's level and deleted the file1.


Also, in the network editor, the input connector for the copy1 Op is divided into 2 and it is parented to the original sphere1 on the left side of the input connector. This one didn't seem to work.

Please do not be confused with parenting & setting up a SOP network.

If one connects, say, Object 1 to Object 2,

Object 1
|
Object 2

then yes, Object 1 is the parent of Object 2.

However, at the SOP level or in the Geometry Editor, connecting a Sphere SOP to a Transform SOP,

Sphere SOP
|
Transform SOP

is not parenting. Instead, it's “connecting the Sphere SOP to the input of the Transform SOP”.

This might seem minor but it is a very important concept that new users must understand.

Cheers!
steven
cyclinggimpe
Thanks for the clear up stevenong. I am very new to Houdini and am trying things out. I understand the copying of the spheres with ctrl-c/ctrl-v; I'm still not sure about the SOP's copying though. Like, when would you use it?

I am working through the Houdini vtm's over at the 3dBuzz site and I believe the next one will be about setting up a network. Maybe I got ahead of myself here with the copying of SOP's.

I used the word Parenting because I didn't know what else to call it. But, I am glad that you cleared it up for me.

Thanks for your help.
will c
halo cycling,

the best way to understand the copy sop might be to simply see it in action. you asked for an example of when you might use it. well, being that halloween is loads of fun, let's make a pumpkin (or a reasonable facsimile). make sure you have your basic three pane setup running (that being the viewer pane, the network editor pane, and the parameters pane). if you don't, simply go to desktops>training to get what you need. also, ensure that all three of your windows are linked and so will all change together as you go from place to place in the program. look in the upper right-hand corner of each pane and you should see a button with a circle on it. likely, this circle has the number 1 in it already. if you click on this button, you will see that you can unlink the window or change its link to 1, 2, or 3. for this little pumpkin making session, make sure each has a 1 in it.

onto the pumpkin!

1. at the object level, lay down a geometry operation (if you don't see one already in the network pane).
2. with the pointer over the network pane, hit enter. this will take you to the sop level so that you can work on the geometry.
3. in the network pane, you may see a file sop. if so, go ahead and delete it.
4. with the pointer over the viewer pane or the network pane, hit tab and type S. this will bring up all surface operations that begin with the letter S.
5. choose the sphere operation.

note: if you did this with the pointer over the view pane, the sphere will appear automatically in the view pane. if you did this with the pointer over the network pane, a little square appears under your pointer. simply click to lay down the sop and it will appear.

6. in the parameters pane, change the radius values x,y, z to 0.7. you can do this interactively by middle clicking and holding on the word radius and using the number ladder to adjust all three values at once. with the middle mouse button still held down, you can drag left to decrease the number and drag right to increase the number. depending on where you have the pointer on the ladder, the values will be adjusted by the increment chosen. once you have the values you like, just release the middle button. play around with that for a minute as it is very handy. in the end, make sure the x, y, z values all read 0.7.
7. again with the pointer over the viewer pane or the network pane, hit tab and type C. like magic, this will bring up all the operations that begin with the letter C.
8. choose the circle operation.
9. in the parameters pane,
a. change the primitive type to nurbs curve
b. change the orientation to the zx plane
c. change the radius x,y to 0.5.
10. now, with your pointer over the network pane, type C again and choose the copy sop. there are different ways you can “wire” these three sops together, but i find i like using the network pane and the manner in which it shows connections.
11. now you have three unconnected sops that you can see in the network pane: sphere1, circle1, and copy1
12. for ease of understanding, make sure that they are layed out like this in the network pane:

SPHERE1 CIRCLE1

COPY1

note: to drag an operation around, simply left click and hold on the picture and drag it around to wherever you want and release. this doesnt affect its translation in 3d space. it's just a way of viewing connections.

13. now, you will notice the sphere sop has an input and an output arrow, the circle sop has only the output arrow, and the copy sop has two input arrows and one output arrow. the dark arrow that is also found on each sop is the bypass option. we won't be using those right now.
14. left-click on the output arrow of the sphere. you will see a dotted line follows your pointer around, that is the connection line. to finish the connection, left-click again on the left input of the copy sop. now the dotted line has become solid.
15. in the same manner, connect the output of the circle sop to the right input of the copy sop.
note: middle click and hold on the left and right inputs of the copy sop and a popup will tell you what each input is expecting.
16. now click on the display flag for the copy sop and WALAA!!! with just a few steps, you now have the beginnings of a decent looking pumpkin.

post-pumpkin analysis (just like ESPN huh?)

so what did we do?

the copy sop placed a copy of the sphere at each point along the circle sop. to see this interactively, make sure the display flag for the copy sop is selected and then click on the picture of the circle sop so that its parameters are displayed in the parameter pane. then change the number of divisions with the slider. you will see that the number of spheres in the viewpane increases or decreases as you increase or decrease the number of points that make up the circle sop. for a pumpkin, the default of 10 seems to look pretty good.

now add a stem with some other tools and you have yourself a pumpkin worthy of even charlie brown!

hope that cleared it up for you.

will c
cyclinggimpe
Will c: Thanks for the tutorial there; I didn't expect one. Seeing as it's late/early morning now, I'll try it out tomorrow before work or on the weekend.

Edit:

I had a chance to create the pumpkin and now have a better understanding of the copy in the SOP's editor. So, if I understand it correctly, you use the SOP's copy that will be a final object (or whatever the term is) from 2 inputs (your sphere the the circle which was the template)? I know you said the divisions in the circle will determine the number of spheres showing in the view pane; but, how does Houdini know to do this? Is it just something that Houdini does (programmed)? It all makes sense while I did your tutorial; but, I don't know if I would have come up with this on my own. I'll have to read more of the pdf's (there's quite a few) and hopefully will have a better understanding.

Thanks for the tutorial.
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