Rubens Abranches Filho

Sadjad Rabiee
Expressions : is some of codes that useful in the channels (parameters) for controlling them.for example $F return current frame number to the some parameter or npoints("..") return number of points for specify object to the some parameters or channel.(It's like expressions in the Maya)

HScript : is old Houdini scripting languages , it's pretty like to Shell Scripting in OS , we can have access to the Houdini with this tool , for example we can add new nodes , or delete nodes , changing display flag or etc.
We should write HScript commands in the Window->HScript Textport
(It's like MEL in Maya)

Python : is new feature for accessing to the Houdini exactly like HScript.we can add New nodes , delete them , edit them ,access to GUI or etc.
Also we can create new custom nodes with Python.

VEX : is a powerful languages for writing new shaders and custom nodes.It's pretty like to C/C++ codes.It's so faster than Python and HScript , even I think in some special cases it can faster than C/C++ tools !!!
we can write VEX codes with two way :
1. writing VEX codes words (like Python , Expressions , HScript)
2. writing VEX codes with Visual Nodes !
in the second method we can write our program only with visual nodes !
for example for writing A * B = C we should add two node for A and B , then add Multiply node and connect A and B to it's inputs , finally connect output of the Multiply node to C node.
We calling this method(Visual) VOP.
VOP nodes are same for different networks (SHOP,POP,OBJ,CHOP,COP,...) , but imported parameters are different for each networks.
for example in the Geometry Network we have P parameter for importing Position of the points , But in the COP network we should have R , G , B parameter for importing RED , GREEN and BLUE to the VOP Network.
So we have different VOP Network for differents Networks such as :
VOP SOP , VOP COP , VOP CHOP , VOP POP and etc


NOTE1 : We can write Python codes as Expression for channels and parameters too , But standard Houdini Expressions is faster than Python Expressions.

NOTE2: We can do some special things with many languages (Python - VEX - HScript).for example we can create a custom node for deforming a geometry with Python and VEX , But VEX is very very faster than others !

Wow, that was really helpful! Thank you so much for taking the time to explain everything in such an understandable way.

As someone who is just starting out with Houdini, do you think it would be more beneficial to focus on learning VEX instead of other languages like Python? Or do you think it's important to get a good understanding of all the languages used in the software in order to master it?

Thanks again for your insights!