changes in Geometry Spreadsheet activate Soft Lock - beginner Questio

[jon3de]

Hi,

I created a curve SOP with the profile of a cup. After connecting it to a revolve sop I recognized that one Point is not exactly welded. In the geometry Spreadsheet I can see it is not located exactly on x/z = 0 which it has to. I thought I could simply change the coordinates in the geometry spreadsheet but this activates the soft lock button in the curve sop which gives me a warning. After unlocking the node the points moved back to its original position. I had to change the coordinates in the curve Sop itself.

So is the geometry spreadsheet just for reading the values? Changing them there means rather a temporary change which doesnt really modifies the node?   

kind regards

Jon

 

Edited August 7, 2015 by jon3de

[3iart]

This is very interesting, it's new... I think... or maybe I have never tried to change the values in the spreadsheet before.

 

It seems to be editing the actual node itself, hence the lock. unlocking reverts the underlying code to default.

 

Try using a point sop, and putting the point number in the group field.

 

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[anim]

well, Soft Lock is not new, it's very old actually

 

Houdini has to store the data somewhere right? So if you edit geo in spreadsheet it will store modification as difference between source data and edited value on the node itself

these attribute delta values are then added to input attribute values, so it's still live, it just has value offset for some attribs on some points etc.

and probably because it's still live it's called Soft Lock, it simply needs input geo to apply modifications to, (possibly with the same topology as it's index based)

it's similar to Paint SOP or Edit SOP caching your painted values and storing differences internally, then aplying them on top of the input data

 

having said that, I would avoid modifying data in spreadsheet unless you are planning to delete history anyway, since this topology dependency makes Soft Lock very sensitive to input changes

Edited August 7, 2015 by anim

[jon3de]

Thank you very much for the detailed explanation.

[lukeiamyourfather]

Directly manipulating the spreadsheet is a very unusual way of working. The "Houdini way" of doing it would be to figure out the root cause of why the points didn't end up where you expected them to be. If a correction is needed then it's best to do it in a procedural way that can be repeated rather than one off changes to a spreadsheet.