MENOZ Posted March 19, 2008 Share Posted March 19, 2008 hello. i'm trying to understand how attributes and variables works. i read this http://www.sidefx.com/index.php?option=com...ighlight=#52982 and now i have sonme question. if variables "are merely a shorthand way to look up a particular attributes value" i could use only attributes,using point() expression, and no variables? if i look in the help of point SOP, i see there are many local variables. so, each of these has a corrispective attribute? if so, that about the $PT varialbe? i'm a little confused... Quote Link to comment Share on other sites More sharing options...
symek Posted March 19, 2008 Share Posted March 19, 2008 (edited) if i look in the help of point SOP, i see there are many local variables. so, each of these has a corrispective attribute? No. Quote from above thread: Both local variables and attributes can refer to the same data (...). But they don't have to. There are a number of variables that don't have a corresponding attributes. $OS, $BB[XYZ], $CE[XYZ]. These are automata to compute for you useful information but they are not directly related to any attribute on geometry (besides centroid is related to geometry position of course ). Edited March 19, 2008 by SYmek Quote Link to comment Share on other sites More sharing options...
MENOZ Posted March 19, 2008 Author Share Posted March 19, 2008 No. Quote from above thread:There are a number of variables that don't have a corresponding attributes. $OS, $BB[XYZ], $CE[XYZ]. These are automata to compute for you useful information but they are not directly related to any attribute on geometry (besides centroid is related to geometry position of course ). thanks a lot! what is $OS variable? if i want to know what is a variable, is there a way to search it in the help? i haven't found anything about $OS Quote Link to comment Share on other sites More sharing options...
Jason Posted March 19, 2008 Share Posted March 19, 2008 thanks a lot!what is $OS variable? if i want to know what is a variable, is there a way to search it in the help? i haven't found anything about $OS Its the name of the current node in which the parameter is evaluated. It's the same as `opname(".")` Quote Link to comment Share on other sites More sharing options...
symek Posted March 19, 2008 Share Posted March 19, 2008 (edited) $OS is a name of the operator executes variable: http://www.sidefx.com/docs/houdini9.1/expressions/_globals or if you don't mind read in Polish : http://www.forum3d.pl/f3dbb/index.php?md=p...d=122878#122878 $OS is global and $BB[XYZ] are locals of course but they both don't have attributes equivalents. Edited March 19, 2008 by SYmek Quote Link to comment Share on other sites More sharing options...
MENOZ Posted March 19, 2008 Author Share Posted March 19, 2008 $OS is a name of the operator executes variable: http://www.sidefx.com/docs/houdini9.1/expressions/_globals or if you don't mind read in Polish : http://www.forum3d.pl/f3dbb/index.php?md=p...d=122878#122878 $OS is global and $BB[XYZ] are locals of course but they both don't have attributes equivalents. it's a global variable! i missed that! thankyou. if i search in the help for each operator, i should find a list of all available locals variables, right? if i look fot the group SOP, there is nothing, but i know can use $CR for example. why it's not listed? Quote Link to comment Share on other sites More sharing options...
MENOZ Posted March 20, 2008 Author Share Posted March 20, 2008 it's a global variable! i missed that! thankyou.if i search in the help for each operator, i should find a list of all available locals variables, right? if i look fot the group SOP, there is nothing, but i know can use $CR for example. why it's not listed? maybe, if in the help are not listed local variables i can use standard local variables? Quote Link to comment Share on other sites More sharing options...
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