MAYA _ Motion path no flip

Sometimes while using motion path, flipping is hard to avoid, here is one solution :
- motion path your main object to the path "path1" blue curve
- duplicate "path1, rename it to "path2", offset it, delete history and edit it to shows the direction pink curve
- create a locator "loc1" and motion path it to the path "path2"
- connect the Uvalue of "path1" to "path2" so they have the same speed
- in the motionpath1 attribute, set follow, object up and in the world up object field enter "loc1"

EDIT : Actually the best method is by far to use a curve on surface as motion path and choose the normal type. To create a curve on surface, first create a surface, then make it live and create a curve on it.

NUKE _ convert 3DTransform to 2DTransform

Reconcile3D node -> create keyframe then link the XY values to a Transform

MAYA / SOuP _ Bmesh to create trees

Apply Bmesh SOuP's node on joint hierarchy to create a base mesh quickly, then adjust the size (not the scale) of each joint to change the width of the BMesh. Can change the position of the joint further, useful for tree/branches.

MAYA / VRAY / MEL _ viewport snapshot in Vray VFB

// Vray VFB viewport snapshot
// create it in maya's renderview then load it in Vray VFB
global proc VrayVFBsnapshot () 
{
 // create snapashot from current viewport camera 
 RenderViewWindow; // open renderview
 string $panel = `getPanel -wf`;
 string $camera = `modelEditor -q -camera $panel`;
 renderWindowRenderCamera snapshot renderView $camera; // create snapshot

 // get path to TMP image
 string $workspaceDir = `workspace -q -fullName`;
 string $imageDir = `workspace -q -fileRuleEntry "images"`;
 string $imagePath =  $workspaceDir  + "/" + $imageDir +  "/" + "TMP_snapshot";
 print $imagePath;
 sysFile -delete ($imagePath+".jpg"); // delete previous snapshot -- Windows
 setAttr "defaultRenderGlobals.imageFormat" 8; // set maya software to .jpg to save it as a jpg
 renderWindowSaveImageCallback "renderView" $imagePath ""; // save snapashot to .jpg file

 // open image in vray vfb
 vrayShowVFB; // open Vray VFB
 vray vfbControl -loadimage ($imagePath+".jpg");
}

NUKE _ merge PNG _ PSDmerge node

Having trouble merging PNG or PSD files with alpha  in nuke?
Use this hidden node to merge them !

nuke.nodes.PSDMerge()

or open a PSD in nuke and click on Breakout Layers and the node will be created.
or tools>other>update  then tools>other>psdmerge

NUKE _ mosaic / pixellate node

Blocky - mosaic effect in nuke
If someone needed a mosaic filter in nuke, no need to turn to 3rd party plugins, or doing resizes, it's right there. Just have to load it, because it's hidden by default. It's called blocky. You can load it in your custom menu.py, by adding these lines, for example:

nuke.createNode("Blocky")

quoted from http://thoughtvfx.blogspot.fr/2011/07/blocky-mosaic-effect-in-nuke.html