Hi!

I was watching CmiFX Houdini fundamentals video, and the instructor David Gary was using $TY value, and i was wondering what is that.

I searched from the help files (Houdini 9.1.244) but didn´t find any mention ablout it.

My question is: what are those “values”? Are there more of those? Is there a some kind of listing, help files maybe?!?!

-KiLa

Hi KILa,

a lot of nodes in houdini have local variables like $TY (which means the y-coordinate of a point btw) . Local variables only having a meaning within a certain node. There isn't really a list of them in houdini9.1 and the only way you can find out about them is to read the help on the SOP you are using. Take a look at the help of the partition, transform, primitive and point SOP and you should have an overview of most of the local variables in SOP-land.

You also have global variables in houdini. They have a meaning in all the different houdini contexts and nodes. For example the $F (current frame number). You should be able to find these in the help.

Hope this clarifies a bit, not the best explanation, but should get you going.


Hans

Hi Hans, thx for you reply!

In my case i have Grid + Mountain + Group. In the group SOP im using expression to select all the points which are higher than 2.

I searched all those nodes but didn´t find any mention about $TY. But in the Group SOP help was this: “…It supports all the local variables of the Point and Primitive operations….” and in the Point SOP there are indeed TX, TY and TZ listed.

In this my case; is the origin of those values the Point SOP?

-Kimmo

Not exactly sure what you mean with “origin of ”those“ values” but if you mean they are the variables explained in the point sop then the answer is yes. The value of the variables are of course the values within your current node. So i guess you have something like this in the Filter Expression in the group SOP: $TY > 2


Hans

Yes - thank you!

-Kimmo