Houville :: iterating in VEX

Urgh, I keep forgetting this. So to iterate in VEX:

//fix negative colours per channel
for ( int i = 0; i < int (3); i++)
{
    if (@Cd[i] < 0) { @Cd[i] *= -1;}
}

Houville :: customising node attributes

Create a text file called "OPcustomize" in your houdini16.0 (or corresponding) folder. Here you can describe the new defaults you want to use with your nodes. For colours

opdefaultcolor Sop null 'RGB 0.0 0.0 0.0';
opdefaultcolor Sop dopnet 'RGB 0.5 0.0 0.0';
opdefaultcolor Sop dopimport 'RGB 0.5 0.0 0.0';
opdefaultcolor Sop object_merge 'RGB 0.475 0.812 0.204';

Thanks to Amber for this one.

Going beyond this:

We can grab the type from a python shell with drag-drop then append ".type()". And we can also work with default and user-defined shapes, and grab the colour info.

# good if you manually selected a new shape.
n.userData("nodeshape");

# good for finding the session default shape for the node
n.type().defaultShape();

# for getting the colour that has been user assigned
n.color()

Example:

opdefaultcolor Driver null 'RGB 0.478 0.478 0.478';
opdefaultshape Driver null 'circle';
opdefaultcolor Driver merge 'RGB 0.65 0.65 0.65';
opdefaultshape Driver merge 'circle';
opdefaultcolor Driver geometry 'RGB 0.145 0.667 0.557';
opdefaultshape Driver geometry 'tabbed_left';

opdefaultcolor Driver gridmarkets::render_submit::1.5.2 'RGB 0.45 0.12 0.6';
opdefaultcolor Driver gridmarkets::nuke::1.19 'RGB 0.976 0.78 0.263';

opdefaultcolor Driver gridmarkets::transcode::1.8 'RGB 0.25 0.5 1';
opdefaultshape Driver gridmarkets::transcode::1.8 'wave';
opdefaultcolor Driver ifd 'RGB 1 .976 0.666';

opdefaultcolor Sop null 'RGB 0.0 0.0 0.0';
opdefaultcolor Sop dopnet 'RGB 1 0 0';
opdefaultcolor Sop gridmarkets::cloud_cache::1 'RGB 0.145 0.667 0.557';
opdefaultshape Sop gridmarkets::cloud_cache::1 'tabbed_left';
opdefaultcolor Sop file 'RGB 0.616 0.871 0.769';

Inspiration :: "No Face"

NO FACE – 千と千尋の神隠し from Raoul Marks – MARXº on Vimeo.

Inspiration :: "Slow Wave"

Slow Wave from andy kennedy on Vimeo.

Houville :: how to not go insane with Nuke vs Houdini hotkeys

Display shortcuts: I have these set as F9-F12

import os,glob
def visualise(flag):
    if flag ==1: hou.selectedNodes()[0].setDisplayFlag(1)
    if flag ==2: hou.selectedNodes()[0].setRenderFlag(1)
    if flag ==3:
        if len(hou.selectedNodes())>0:
            state = 1-hou.selectedNodes()[0].isTemplateFlagSet()
            for i in hou.node(os.path.dirname(hou.selectedNodes()[0].path())).glob('*'): i.setTemplateFlag(0)
            for i in hou.selectedNodes():
                i.setTemplateFlag(state)
    if flag ==4:
        state = 1-hou.selectedNodes()[0].isBypassed()
        for i in hou.selectedNodes():
            i.bypass(state)

visualise(4)

This is straight out of Nukeland for snapping your nodes to the grid intersections. I have it set as Shift+\

And finally the most common one I need to not yell at the everlasting cookfests. I have it set to Alt+Shift+U, which is a bit Vulcan MindMeldy but it works. I also set Alt+U to "/Houdini/Force Update"

import hou
mode = hou.updateModeSetting().name()
if mode == 'AutoUpdate':
    hou.setUpdateMode(hou.updateMode.Manual)
if mode == 'Manual':
    hou.setUpdateMode(hou.updateMode.OnMouseUp)
if mode == 'OnMouseUp':
    hou.setUpdateMode(hou.updateMode.AutoUpdate)

NukeStudio :: Return the source path for a selected clip

from hiero.core import TrackItem
seq = hiero.ui.activeSequence()
te = hiero.ui.getTimelineEditor(seq)
t =te.selection()[-1]
print t.source().mediaSource().fileinfos()[0].filename()

NukeStudio :: Text expression to display media info

Use this to get file name of the displayed media in NukeStudio:

[lindex [split [metadata input/filename] "/"] end]

Alternatively...

if you have a comp clip on the time line, this will help you get the internal frame number:
[metadata input/frame]

For Shot name:
[metadata hiero/shot]


For Clip name:
[metadata hiero/clip]


For the file path of the Clip:
[metadata input/filename]


For the Sequence time frame no.
[frame]

For the source clip frame number:
[metadata input/frame]

Houville :: nice up vectors

This is for arranging your geo for nice behaviour with the copy sop. If you want to distibute geo, like trees or whatever, and control orientation but still respect the angle to the surface this is for you.


You'll need some way to connect the target points with the surface prim they relate to. Scatter has the sourceprim option which is cool, but if you want to manually do it you'll need a pre-pass. Here's an example using the 'stick a point in the middle of the face' technique. This should run over prims.

int newPtNum = addpoint(0,@P);
addpointattrib(0,"sourceprim", 0);
setpointattrib(0,"sourceprim", newPtNum, @primnum, 'set');
removeprim(0,@primnum,1);

Now lets get the surface geo ready. Here we will sneakily say normals run along the U direction and Up is what would typically be considered a normal. This makes sure our orientation makes sense.

Run this over points, assuming point source is in OpInput1, and reference geo for orientation is OpInput2.

vector center = primuv(s@OpInput2, 'P', i@sourceprim, {0.5,0.5,0.0});
vector dPdu = primuv(s@OpInput2, 'P', i@sourceprim, {0.51,0.5,0.0});
vector dPdv = primuv(s@OpInput2, 'P', i@sourceprim, {0.5,0.51,0.0});

vector u = normalize(dPdu - center);
vector v = normalize(dPdv - center);

v@up = normalize(cross(u,v));
v@N = u;

//matrix rotation shiz!
vector rot[];
rot[0] = u;
rot[1] = v@up;
rot[2] = v;
matrix3 mtx[] = unserialize(serialize(rot));
rotate(mtx[0], radians(chf('heading')), v@up);
rot = unserialize(serialize(mtx));
v@N = rot[0];
v@up = rot[1];

** for another post - passing colour information through points to be picked up by "Point Instance Procedural" as material overrides:

string r = sprintf("%d", @Cd.x);
string g = sprintf("%d", @Cd.y);
string b = sprintf("%d", @Cd.z);


s@shop_materialpath = chs('../theInstancesShaderPath');
s@material_override = "{'basecolorr':" + r + ",'basecolorg':" + g + ",'basecolorb':" + b + ",}";

Soooooo.. some of that was overkill. Here are a few ways to optimise that.

You can for example dispense with the serialise/unserialise phase by seting to the matrix directly. Also you can use quarternion to directly pull rotation information out of the matrix. Bear in mind Houdini understands '@orient' as a vector4 aka p@orient.

## direct casting and assignment of a matrix, rotation, extraction as a quaternion.
matrix3 rot = set(u,v@up,v)
rotate(rot, radians(chf('heading')), v@up);
p@orient = quaternion(rot)

And finally, you don't have to derive a @up if you have a normal. Have the points (scattered or otherwise) pick up their normals from the source they are based on. addpointattrib(0,"N",{0,0,0}); setpointattrib(0,"N",newPtNum,@N,"set");

Python: copy paste buffer

Seems like PyQt4 is the ideal way to go:

Two styles:

##how to get something into the clipboard / copy/paste buffer
from PyQt4 import QtGui
QtGui.QApplication.clipboard().setText(textString)

##and to get it back out
text = QtGui.QApplication.clipboard().text()

##but it will be a QString so you'll probably want to 
textString = str(text)

In some cases PyQt4 seems to be crippled, so you can also use Tkinter, which seems to work well for extracting from clipboard. Haven't had luck putting stuff in though:

import Tkinter
root = Tkinter.Tk()
root.withdraw() # Hide the main window (optional)
rawClip = root.clipboard_get()

Nukia - smarter switch

Use in text node to find what Switch1 Reads are looking at. [lindex [split [file tail [value [value Switch1.input[expr int([value Switch1.which])].name].file]] -] 0] or lol.. [lindex [split [file tail [value [value [value this.input0.name].input[expr int([value [value this.input0.name].which])].name].file]] -] 0] This is also useful. Root dir: [file dirname [knob [topnode].file] ] File name: [file tail [knob [topnode].file] ] File extension: [file extension [knob [topnode].file] ]

Houville :: rop presets

nodePath = ropnet.createNode('ifd',node_name).path()
hscript = "oppresetloadfile %s %s" % (nodePath, "niceRopLayout.preset")
hou.hscript(hscript)

Houville :: put points in the centre of prims

Points in centre of prim, and delete points:

addpoint(0, @P);
removeprim(0, @primnum, 1);

==EDIT== Just realised it can be handy to pull attributes from the prim on to the newly created points in the same primwrangle.
Here's how:

int newPt = addpoint(0, @P);
addpointattrib(0,"N",{0,0,0});
setpointattrib(0,"N", newPt, @N, "add");
removeprim(0, @primnum, 1);

Houville :: copying nodes from one part of network to another

Yup, this might come in handy too:

hou.copyNodesTo(hou.node('/obj/mySubnet').glob('*'),hou.node('/obj'))

Houville :: adding params to a obj

Another one I keep forgetting... Here's how to add params to a node in houdini.

n = hou.node('/obj/geo1')
n.addSpareParmTuple(hou.IntParmTemplate('intParm','',1, default_value=(10,),min = 0, max = 20))
n.addSpareParmTuple(hou.FloatParmTemplate('floatParm','',1, default_value=(10,),min = 0, max = 20))


#define some multi line code.  Like a python script
code = """print 'some stuff'
print 'more stuffs'
print 'an\\\\' ting'"""

# is hidden is good for hiding code away
n.addSpareParmTuple(hou.StringParmTemplate('stringParm','',1,default_value=(code,), is_hidden=0))
n.addSpareParmTuple(hou.ButtonParmTemplate('Button','', join_with_next=0, script_callback='exec(hou.parm("stringParm").evalAsString())', script_callback_language=hou.scriptLanguage.Python))

And when you want to delete some parms, remember to get rid of the tuple.  You can access that easily like this:

n.removeSpareParmTuple(n.parm('stringParm').tuple())

And finally, if you don't want to add params one by one you can make a Parameter Template Group to then add as a lump later.

ptg = n.parmTemplateGroup()
ptg.append(hou.IntParmTemplate('intParm','',1, default_value=(10,),min = 0, max = 20))
n.setParmTemplateGroup(ptg)

Not quite sure yet why this is better, but I'll probably find out one day.

Retro bunker

https://omgfacts.com/this-70s-style-bunker-is-part-creepy-part-awesome-c13a7a87e088#.7pi0s2sdg

Splinter :: #0002 - Snow Scavenging Koutasquow

[full size here]

Splinter :: #0001 barren except for a fabricated sky