What is OTL and what is HDK in Houdini

[ISUther]

I did Google it and got bit confused.
Can some one xplain me diferences of those 2?

[catchyid]

I am not expert here, but I think: OTL ( Operator Type Library) , which you can think of as a function, that takes some input (e.g. a mesh) and computes an output (e.g. point normals). In Houdini, everything is done via functions, but they call them "nodes", so there is one node to compute normals, another node to color an object,... So when you build your scene, you use a bunch of node to create whatever you want to do... (to over simplify it, an OTL is just another name for the "node" concept)

There are different ways where you can make OTL, you can put together other nodes to make OTL. ALSO, you can write C code to make your OTL node. Using C code requires that you use HDK (Houdini Development Kit), which is basically a set of C/C++ libraries that you can use to build your Houdini nodes.

So, OTL is just a node. HDK is one way to build an OTL.

[ISUther]

Thank you for this.
Now i understand it better
And can study my another Project that i may be can finnish one day

[michael]

an OTL is an Operator Type Library - but the new term for then is HDA - Houdini Digital Asset.

an HDA is a tool, many of Houdini's built in tools are in fact HDAs - put down a Color SOP and then dive inside - you'll see it is made of a number of other nodes, wrapped up in a package with a bunch of parameters.

you can make your own HDAs as well.

 

the HDK is the Houdini Development Kit - these are the files that you would use to compile your own nodes built with C++

both of these topics are talked about in the Docs.

 

HTH