H O U D I N I   S T E P S

If you are reading this page, then you clicked on the Houdini 9.1 render, and you want to know how to continue modeling your palm, utilizing the

stamp() function in the "copy" node.

In this page, we will also animate and texture our palm, using both PRMAN in Vex, and writing an .otl in Cutter to work as a shader in Houdini 9.1.

At this point, you should already have what I am calling your "Middle" branch modeled using random values only partially. Now we will create three layers of branches, all with random bends and curves in order to give the tree a natural feeling.

For a text only version of this page please click HERE.

We will start by adding another copy to the bottom of our tree. The last node in-line at the moment should be a "twist" for the animation aspect of this. Connect the "copy", and apply values for the

Stamp Inputs like we did for the leaves.

Next, we have to undo some of the values we gave nodes between the "merge" and the "copy".

We'll start with the "twist" since it is furthest up the tree. I made a fucnction in the stamp inputs for a variable called "twist", now we will use it to replace the value in the "Strength" of the "twist".

stamp("../copy7"/ twist, .1)

The "twist/bend" also has a value waiting in the "copy", in the "Strength" parameter

write a stamp() expression that calls the variable from the "copy".

If you cannot figure it out, click the image below for details.

In the "xform" I added an expression that keeps the stalk, or stem, of the branch in the same spot as the bend tries to moves it.

Finally the animation information is going to be in the last "twist/bend" of the tree befor the copy. Again, we are going to use the stamp() to start the branches at different times and make their paths slightly vary in order to keep with the random style of the palm. The particular Palmetto I choose, the Sago Palm bush has a short range of motion. Having a much stiffer stem, with more closely grouped leaves, it's movement is subtle and mostly near the end of the branch.

Here we see a profile of the group, and you can notice,

even without animation,

that the angle of those branches is random

Finally, we pull all of the branches together!

Thanks for looking!

Renderman Palm Renders
Tutorial Part 4: Writing a PRMan Shader Using VEX
Tutorial Part 5: Creating .otl in Cutter to Work in Houdini