"catch" command frequency?

[bentllama]

using the "catch" command:

    ie: catch (`select -add "f\_hip"`);

Q: Is it wrong to use the "catch" command very frequently in a script? I have heard it may slow it down a bit, but I need a way of perfoming an action IF an object exists in a scene..."catch" seems like the easiest way to do that with the least amount of lines of code...

What is your opinion on this?

Thanks.

[gmask]

I only use it when I have a command that could easily fail. Suppose you have a script that might fail if certain types on incompatible nodes might be in your selection for example. You could take the time to make sure that the script parses out teh correct nodes or you could just use the catch function to ignore them.

I would say that it depends on what you are writing and who is goign to be using it.

For a complex script that is intended to be used by other peopel then you need to build in error correction and someway to handle potential problems. If there are incorrect nodes in the selection that interfere witht he operation you should put up a dialogue box that warns the user of this or have your script filter them out. If you use the catch function as a filter then there may be instances were some errors are not reported even when you have the correct selection and the user may not know why.

In short there is not need to put catch on every single command issued and I would not use it frequently in scripts that are going to be used by other users in substitution of warnign messages and proper scripting UI.

[bentllama]

Perhaps I should have stated what I am using the "catch" for...

The scripts I am authouring with "catch" are hard-coded for specific character structures in our game. For the most part these scripts are used to attach character meshes to game skeletons, general parenting, auto-rig, etc...

eg: catch (parent m\_r\_toe b\_r\_toe); //parent mesh to skel

We have X number of characters and they share the same naming convention scheme...

Therefore I need to do the same functions to most characters but need to account for slight differences in heirarchy and node structure between characters...and some nodes not being present.

For instance, one character could have a regular human hand while the other could have something more alien. I need to account for that node difference without having to augment each separate character script. I am not collecting attr data for use elsewhere in these scripts...and if I was doing that a simple IF statement would suffice.

Perhaps I am jhust being lazy here and an IF statement is better. I just thought that "catch" requires one line and is generally accepted to be OK.

So given the new knowledge about my situation, do you have a different opinion?

Thanks again for responding, gmask. I appreciate it.

[gmask]

That sounds okay.. you might want to add some logging of the catchs so that afterwards you know w aht wasn't there or didn't get parented.

[jimtheartist]

It sounds like for your specific need, that is exactly what you want. When I encounter a similar situation I just use an 'if' statement and call my little 'isThere' function which simply returns a 1 or 0, no data about the attribute is needed and I don't have to worry about how fast or slow the 'catch' statement is.