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ikoon

edit Curve SOP's @P within the "Geometry Spreadsheet" and the "Soft lock"

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Hello, please:

- I have a curve SOP with few points
- then I edit the @P within the "Geometry Spreadsheet" 
- the new @P are not transferred into the Coordinates and the Curve SOP gets "Soft Lock"

I have tried to find a help about the Soft Lock and it seems to be obsolete

- can I transfer the edited @P or other attributes to the SOP node?
- is there some other user friendly way to edit for example Curve SOP Coordinates? The line input with commas is not user friendly.

Thank you very much for patience with my noob questions :)

Edited by ikoon

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Hi,

1) geometry spreadsheet is not intended for dialing in values. so I would advise you not to do it. use Parameter spreadsheet if you want to modify the values in a spreadsheet manner rather than in network view.

2) if you want to edit individual points on the curve, the most straightforward way is the Edit SOP. you can then manipulate the points directly in viewport.

3) if you want to type exact numbers for each point, I would consider using the Add SOP instead of curve SOP.

4) you can can manipulate existing points with wrangle SOP or point VOP but typically you don't want to do something that cumbersome.

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Hello David, thank you very much. I am exploring all the things you have mentioned and I think that I understand. Thank you.

As regards the Parameter Spreadsheet:

  • I have only seen the names of parameters in the Parameter Tree view. I see in the help file that is not to get overloaded.
  • so I have put * in the Parm Mask ... and now I can see one row for my Curve, one column for Coords
  • but I cannot access the coords in the tree view ... am I doing something wrong, please?

I have attached the screenshot.

 

sheet.PNG

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Hi,

nothing wrong about anything you're doing. parameters can't be selected in Houdini. you can only select nodes/objects. each node is displayed in the separate row. parameters that match the Mask are then listed in the columns. if you want to see only the coordinates then type it into a Parm Mask instead of * character.

Personally, I'd advise you to try a different approach as this way you are probably not getting what you want. Trying to stick to the spreadsheet is only making things difficult for you. Can't be more specific as I don't know what exactly are you trying to do.

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I've faced this situation, and it's really not intuitive to work on curves.

Not being able to type in the points coord is sometime very frustrating. There's work arounds, but they are only work arounds... (add points and snap / wrangle points ...)

The curves node allow you to manually move in the viewport any point, but only one at a time. Why? I don't know.

I don't know if it's already in H16 wishlist, but it should.

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cyril: well, that is why I suggested to use the Add SOP where you can type in the coords directly. if you want to move multiple points at the same time, simply use Edit SOP.

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david, ok, but does it makes it intuitive/comfortable ?

I'm wondering why limiting the manual modification to one point at a time (I guess there's a reason behind) in the curve node.

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certainly there is a room for improvement (as always), I'm fine with this workflow though. you have more simple tools that you can combine instead of one blackbox tool that does it all. sounds like Houdini to me :)

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Thank you very much. I am just learning what Houdini can do ... to use it the most effective way afterwards. I was not sure if there is some command or hotkey to accept the changes in the "soft lock"

Another thing regarding the Geometry Spreadsheet, once I needed this:

  • sort by some important attribute
  • select the points in the GS and then edit them in the viewport
  • see the attachment ... but you cannot select points/prims in the Geometry Spreadsheet, am I right?

I did the selection with the Attribute Wrangle:

if (@myAttrib > 0.6) @group_foo = 1 ;

 

select.PNG

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Man it looks like you really love spreadsheets :D

Let me try a little explanation on spreadsheets in Houdini if you don't mind. You are obviously going through the similar difficulties as I did when I stared learning Houdini.

In general, spreadsheets are not a tool for selecting a geometry or manipulating attributes. Selecting geo with wrangle as you did is totally legit.

Geometry spreadsheet allows you to see, filter and sort the attribute values on the geometry. it is giving you an overview. nothing else. no selections, no changing of values. just a list, but the essential one.

Parameter spreadsheet allows you to manipulate node's parameters. It shows exactly the same thing as Parameters tab. Only it is arranged as a spreadsheet and allows you to quickly filter the objects and display desired parameters without diving into networks. Handy but other than that it doesn't have any extra functionality.

Either of the spreadsheets doesn't allow you to manipulate the attributes directly. Don't confuse attributes and parameters - parameter is a part of the user interface and you can use it to drive the attribute(s) that it's connected to (i think it is safe to say it this way :)). The reason for this limitation is that geometry manipulation happens with the help of nodes where these manipulations are stored. So if you do a change to the point position in the spreadsheet or in the viewport, the program has to create a node for you to do that manipulation. That happens in any modeling package automatically with the exception of Houdini where you have to create and wire the nodes yourself and that is why spreadsheet actions are kind of limited.

Obviously, both approaches have its pros and cons. In non-Houdini packages you have to use sort of extensions in the form of spreadsheets and dense interfaces to access predetermined pieces of data that are otherwise hidden (cool for some tasks as it is much simpler). In Houdini, all data is exposed, many tools are disassembled and lots of user actions are therefore moved to a lower level (to the nodes) with all its advantages and difficulties. Spreadsheets are still here but they serve a slightly different purpose as you don't need them for accessing the data any more.

Sorry for possibly pointing out some obvious things to you, but I find this important to understand. For me personally, this difference in how user can manipulate data and how to use it to his advantage was the toughest thing to overcome at the beginning.

Hope that helps. cheers, D. 

 

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Hello David :) you are great. Your post and all the people from this great forum encourage me to learn Houdini. Houdini is sometimes frustrating for me ... it is like pulling strings in some mixed spider web :) ... but I understand it more, now. And I also see, that I have to "give up" and learn the basics, understand the principles and then I will be efficient. Maybe in a year, maybe in five :) with you guys it is possible. I hope I will also help.

Thank you. Sorry for my "english"

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I see two reasons to learn Houdini ... to be able to use it and to be a part of this community :) money is not everything :)

Edited by ikoon

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Quote

Geometry spreadsheet allows you to see, filter and sort the attribute values on the geometry. it is giving you an overview. nothing else. no selections, no changing of values. just a list, but the essential one.

Hmm, I just tried selecting entries in the geometry spreadsheet and clicking the little icon next to "Attributes" that looks like an equal sign.

When in select mode in the scene view, this selection from the geometry spreadsheet does indeed become active. And I can put down for example an edit SOP to move said points :)

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Hamp: you're right! just tried that and it works. Handy! :) didn't know about this. looks like a more recent addition. 

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Found it just the other day myself hehe.

While it doesn't solve the editing of actual p values it seems handy in many situations, if only to visualize which points the list refer to in 3D space or create impromptu cluster selections.

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Great, Hampus, thank you :) But I think that it is buggy, unfortunately. It works, when the sheet is sorted by the ptnum. When I sort the sheet by an attribute, for example P[z] and then select rows 0-3, I get selected points with ptnum 0-3.

Edit: Now who is going to tell SESI "Thank you, but ... " :)

Edited by ikoon

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Bummer, please go ahead and file a Bug report/RFE.

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I have downloaded the daily build and it is still buggy. So I have reported it to SESI.

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Hi all, I would like to mention that you can use stash node and then, you can edit contents directly in geometry spreadsheet.

Now, I'm having a similiar problem where I need the ability to edit individual parameters of a prim. 

The use case is like this: I have thousands of building footprints in one node (imported as geodata from OSM) and they contain attributes from which I generate building - like height.. and would like to fine-tune imperfections (for example modifying this said height attribute individually for each building where this is needed) so that after this attribute for that particular building is modified, the building can be procedurally re-generated to reflect changes.

I am unable to find solution anywhere although this seems to be a common use-case IMHO (meaning to edit subset of geometry node) so I'm trying this thread which discusses similiar things.

Ideas (if houdini really doesn't have any tool to handle this):

  • have each footprint as separate node - not possible bc I have thousands of these footprints which will result in lots of nodes (plus I'm using lot of vex to effectively calculate other stuff like occlusions with roads.. which would be extremely slow if done as separate nodes..)
  • use stash node as mentioned above - possible but cumbersome - can only input text or number - lacking support for combo-boxes, sliders, checkboxes.. to be more user friendly  - it's expected lot of people (not devs, just regular users) will work on this and adjust large amount of these prims' attributes every day)
  • make a python shelf tool and show a pyside2 gui based on prim that's selected where I can edit these individual attributes - I did that only to found out that it isn't possible to edit geometry this way (due to permission error geometry is read-only) - thus only way to do this is using python SOP
  • I used python SOP, added a button that references other python SOP (so that it can be run on demand bc this is plugged into procedural code) and did similiar pyside gui based on selected prim in viewport - looks like something is working but it freezes houdini in weird way (something works, something stops working), gives me Infinite recursion in evaluation error even though I cannot find any infinite loop in my code an I cannot recover from this - even if I remove affected code houdini stays frozen and I have to restart it.. - I can share code if anyone is interested but even though this looked promising, I don't know if this is the correct approach
  • any other ideas?

Any help is greatly appreciated. I love houdini bc it is much more capable than any other tool on the market but this gives me headache for weeks now.. 

btw I created similiar post here if you want more info/different explanation but no replies yet.. :( 

 

Edited by mara_91

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