Hi David,
Although deep-compositing might be the prefered solution you can create
Holdouts for your particles if you have the camera (translations) you
used to render both CG objects and particles. Using the Camera, you can
create a depth pass (if not already existing) using an expression node.
Using the depth and a MergeExpression or by substracting the depth
channels, you can create a holdout matte. See attached script for
further details. You can save the included Holdout (group) node as a gizmo.
Don't use the DeepHoldout node if you don't have deep input since it's
really slow.
Cheerz,
Mitja
On 24.07.2014 03:57, David Rutherford wrote:
I have searched pretty thoroughly but so far I have not been able to
find any information on how to use a world position pass to comp two
CG objects together. I have a bunch of test objects rendered with a
separate beauty pass and a world position pass and a particle cloud
rendered with an embedded world position pass. I want to comp them
together so that the particles are merged correctly surrounding the
objects both in front and behind. The goal is to do away with hold
outs in the particle render.
What is the work-flow for doing this. Do I need more than the world
position pass? Is this what is labelled "deep" compositing or is this
actually something else.
Any pointers, tips or a link to a tutorial would be greatly appreciated.
David.
#! C:/Program Files/Nuke7.0v5/Nuke7.0.exe -nx
version 7.0 v5
define_window_layout_xml {<?xml version="1.0" encoding="UTF-8"?>
<layout version="1.0">
<window x="0" y="0" w="1936" h="1050" screen="1">
<splitter orientation="1">
<split size="40"/>
<dock id="" hideTitles="1" activePageId="Toolbar.1">
<page id="Toolbar.1"/>
</dock>
<split size="1876"/>
<splitter orientation="1">
<split size="545"/>
<dock id="" activePageId="DAG.1">
<page id="DAG.1"/>
<page id="DAG.3"/>
</dock>
<split size="1327"/>
<splitter orientation="2">
<split size="793"/>
<dock id="" activePageId="Properties.1">
<page id="Script Editor.1"/>
<page id="Error Console.1"/>
<page id="Properties.1"/>
<page id="de.hkh.nukeTACTIC.Panel"/>
</dock>
<split size="192"/>
<dock id="" activePageId="Error Console.2">
<page id="Error Console.2"/>
</dock>
</splitter>
</splitter>
</splitter>
</window>
<window x="1920" y="0" w="1920" h="1080" fullscreen="1" screen="0">
<splitter orientation="2">
<split size="1080"/>
<dock id="" activePageId="Viewer.1">
<page id="Viewer.1"/>
</dock>
</splitter>
</window>
</layout>
}
Root {
inputs 0
name C:/Users/Mitja/Desktop/Holdout_from_P.nk
format "2038 1080 0 0 2038 1080 1 bieneMaja_2K"
proxy_type scale
proxy_format "1024 778 0 0 1024 778 1 1K_Super_35(full-ap)"
int8Lut linear
int16Lut linear
views "Left #ff0000
Right #00ff00"
views_colours true
}
BackdropNode {
inputs 0
name BackdropNode1
tile_color 0x8e8e3800
label Footage
note_font_size 42
xpos -545
ypos -753
bdwidth 489
bdheight 417
}
BackdropNode {
inputs 0
name BackdropNode2
tile_color 0x388e8e00
label "Create depth from P and Convert depth to 1/z style"
note_font_size 16
xpos -558
ypos -277
bdwidth 511
bdheight 291
}
BackdropNode {
inputs 0
name BackdropNode3
tile_color 0x71c67100
label "Create Holdout and Merge"
note_font_size 42
xpos -561
ypos 61
bdwidth 515
bdheight 202
}
Constant {
inputs 0
channels rgb
color {0.8700000048 0.4472624958 0.3378186822 0.7049999833}
name Constant2
xpos -146
ypos -634
}
Sphere {
translate {0.3350000083 0.3799999952 -0.6399999857}
name Sphere1
xpos -146
ypos -517
}
set N15e2dd00 [stack 0]
Constant {
inputs 0
channels rgb
color {0.1112499982 0.3648999035 0.4449999928 0.7049999833}
name Constant1
xpos -404
ypos -638
}
Cube {
name Cube1
xpos -404
ypos -519
}
set N15e2cf40 [stack 0]
Scene {
inputs 2
name Scene1
xpos -278
ypos -673
}
Camera2 {
inputs 0
translate {10.31969833 2.860922098 7.005442142}
rotate {-12.99999894 55.39999904 0}
name Camera1
xpos -680
ypos -474
}
set N15e2cbd0 [stack 0]
push $N15e2cbd0
push $N15e2cf40
push 0
ScanlineRender {
inputs 3
motion_vectors_type distance
name ScanlineRender1
xpos -404
ypos -469
}
add_layer {P P.X P.Y P.Z P.red P.green P.blue P.alpha}
DepthToPosition {
inputs 2
output P
name DepthToPosition1
xpos -404
ypos -387
}
set C15e2d620 [stack 0]
Dot {
name Dot1
label CG
xpos -370
ypos -193
}
set N15e2e070 [stack 0]
Shuffle {
in P
name Shuffle2
xpos -521
ypos -128
}
set C218d21d0 [stack 0]
Expression {
channel3 {none none none depth.Z}
expr3 "sqrt( pow( ( red - cam_translate.x ) , 2 ) + pow( ( green -
cam_translate.y ) , 2 ) + pow( ( blue - cam_translate.z ) , 2 ) )"
name generate_depth_
xpos -521
ypos -104
addUserKnob {20 User}
addUserKnob {13 cam_translate l "Camera Position"}
cam_translate {{parent.Camera1.translate.Left} {parent.Camera1.translate.Left}
{parent.Camera1.translate.Left}}
}
set C10f1a320 [stack 0]
Expression {
channel3 {none none none depth.Z}
expr3 "1/ depth.Z"
name convert_depth
xpos -521
ypos -80
}
set C1b0d05e0 [stack 0]
push $N15e2e070
Copy {
inputs 2
from0 -rgba.alpha
to0 -rgba.alpha
channels depth
name Copy1
xpos -404
ypos -48
}
set C1b0d0950 [stack 0]
set N1b0d0950 [stack 0]
push $N15e2cbd0
push $N15e2cbd0
push $N15e2dd00
push 0
ScanlineRender {
inputs 3
motion_vectors_type distance
name ScanlineRender2
xpos -146
ypos -453
}
clone $C15e2d620 {
inputs 2
xpos -146
ypos -376
selected false
}
Dot {
name Dot2
label Particles
xpos -112
ypos -199
}
set N15e2e750 [stack 0]
clone $C218d21d0 {
xpos -263
ypos -131
selected false
}
clone $C10f1a320 {
xpos -263
ypos -107
selected false
}
clone $C1b0d05e0 {
xpos -263
ypos -83
selected false
}
push $N15e2e750
clone $C1b0d0950 {
inputs 2
xpos -146
ypos -46
selected false
}
Group {
inputs 2
name Holdout
help "Creates a holdout from two depth channels (depth must be 1/z style).
Author: Mitja Müller-Jend\nemail: [email protected]"
knobChanged "def hideShowKnobs():\n\n #this = nuke.selectedNode()\n this
= nuke.thisNode()\n \n knobModes = \{'Compare' : \[ 'depth_erode_size' ],
'Grade': \['softness', 'offset'] \}\n method = this\['method'].value()\n\n
for knobMode, knobs in knobModes.iteritems():\n for k in knobs:\n
if this.knob(k):\n this.knob(k).setVisible(method ==
knobMode)\nhideShowKnobs()\n"
xpos -146
ypos 133
addUserKnob {20 holdout_tab l Holdout}
addUserKnob {4 method l Method t "<b>Compare:</b> Compare depth channels using
Merge Expression: Az<=Bz?1:0\n<b>Grade:</b> Get Matte from substracting and
grading depth channels." M {Compare Grade "" "" "" "" "" ""}}
method Grade
addUserKnob {26 div1 l Holdout}
addUserKnob {14 depth_erode_size l "Erode Depth" +HIDDEN R -100 100}
addUserKnob {19 softness l Softness}
addUserKnob {19 offset l Offset R -1 1}
offset {0 0 0 0}
addUserKnob {26 ""}
addUserKnob {20 post l "Post Erode/Blur" t "Erode and Blur holdout mask before
multiplying with alpha." n 1}
addUserKnob {14 erode l "Erode Mask" R -100 100}
addUserKnob {6 matrix_blur l "Matrix Blur" +STARTLINE}
matrix_blur true
addUserKnob {20 endGroup n -1}
addUserKnob {26 post_group l INVISIBLE +INVISIBLE T obsolete}
addUserKnob {26 pre_group l INVISIBLE +INVISIBLE T obsolete}
}
Input {
inputs 0
name BG
xpos -576
ypos -553
number 1
}
Dot {
name Dot3
xpos -542
ypos -513
}
set N9e40d780 [stack 0]
Shuffle {
in depth
name Shuffle1
xpos -708
ypos -432
}
set C9e3812c0 [stack 0]
Input {
inputs 0
name FG
xpos -332
ypos -524
}
set N9e381630 [stack 0]
Dot {
name Dot1
xpos -841
ypos -446
}
clone $C9e3812c0 {
xpos -875
ypos -428
selected false
}
Merge2 {
inputs 2
operation from
name Merge14
xpos -875
ypos -367
}
Grade {
channels rgba
whitepoint {{"(parent.softness / 100 )+ 0.00001"}}
add {{"parent.offset + 0.5"}}
white_clamp true
name compare_grade
xpos -875
ypos -338
}
set N9e3823f0 [stack 0]
Clamp {
name Clamp1
xpos -875
ypos -295
}
Dot {
name Dot2
xpos -841
ypos -259
}
push $N9e40d780
FilterErode {
channels depth
size {{parent.depth_erode_size}}
name FilterErode_Depth
xpos -576
ypos -434
}
push $N9e381630
MergeExpression {
inputs 2
expr3 Az<=Bz?1:0
name Holdoutmask
xpos -576
ypos -343
}
Switch {
inputs 2
which {{parent.method}}
name Switch1
xpos -576
ypos -262
}
FilterErode {
channels alpha
size {{parent.erode.w} {parent.erode.h}}
name FilterErode_Mask
xpos -576
ypos -173
}
Matrix {
matrix {
{1 2 1}
{2 4 2}
{1 2 1}
}
normalize true
name Matrix1
xpos -576
ypos -137
disable {{!parent.matrix_blur}}
}
push $N9e381630
ChannelMerge {
inputs 2
operation multiply
name ChannelMerge6
xpos -332
ypos -143
}
Output {
name Output1
xpos -332
ypos -32
}
push $N9e3823f0
Viewer {
gain 0.96
input_process false
name Viewer1
xpos -748
ypos -314
}
end_group
Premult {
name Premult1
xpos -146
ypos 157
}
push $N1b0d0950
Merge2 {
inputs 2
name Merge1
xpos -404
ypos 208
}
Viewer {
frame 1
input_process false
name Viewer1
selected true
xpos -404
ypos 407
}
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