Hi,

Please help me … :cry:

I am having to switch over from maya to houdini. I am very experienced with maya and I have done just fine with the basic tutorials with houdini but I am getting a bit overwhelmed or frustrated, I must admit, in just trying to translate 3d sthings I would do in maya for their equivalents in houdini ;

Is there anyone else there that knows both softwares and can point me to the correct terms or methods in Houdini for doing ;

clusters
freeze transformations
goalPP
particle i.d. and expressions
poly average
snap to vertice
blendshape snapshot
point, orient and parent constraints

So many others …. but these are the ones that are really stopping me in my tracks at the moment in translating things from maya.

thank u

as someone who has done the switch myself…
I'd really recommend thinking about what you want to do rather than what /tool/ you would have used in maya to do it…
this will help you and save time when looking through the documentation…

but as for some of your specifics…

clusters

- nope, sorry…no such thing…look at sticky and rivet - but note they WILL NOT do what clusters do

freeze transformations

in maya (if memory serves) this just jams the transformations into a pre-transform…
in the docs:
Set an object's pre-transform

* Home
* ▶
* Modeling
* ▶
* Objects
* ▶
* Set an object's pre-transform


goalPP

goal weight per particle?…that's in maya's softbodies yeah?…not sure what the Houdini equivalent would be if any…

particle i.d. and expressions

read though the pops docs…particle ID will be an attribute of a particle

poly average

not sure what this means…

snap to vertice

check the docs:
Snapping

* Home
* ▶
* Modeling
* ▶
* Modeling tools
* ▶
* Snapping

blendshape snapshot

not sure what this means….could it be the idea of making a blendshape target?…look into the textport, type “exhelp sopcreateedit” without the "

point, orient and parent constraints

docs:

Blend

* Home
* ▶
* Operators
* ▶
* Object tools
* ▶
* Blend

Blend

* Home
* ▶
* Operators
* ▶
* Objects (OBJs)
* ▶
* Blend



hope that helps…

if you're trying to something specific just do your best to describe what it is and you're sure to get some great advice.

chrisw: The two programs are very similar, but definitely not the same. If you're making the switch at a place where you work, ask the people working there for guidance. Explain the way these features work and ask how you would do something in houdini. If you're making the switch at home in your spare time, then relax and just try to learn houdini for what it is.

can't speak for Maya but the rigging is MUCH more straitforeward than in Max, the connections on the object level mean child-parent/hirarchy. Very clever, there's also a very powerful blend on the object level which lets you selectively blend parents.

The hard thing for me to understand was definately how attributes work with the particles. Just think in Houdini it's XYZUW + anything else you want. These attributes can do just about anything you want with particles / geometry / or textures.

Copying/instancing/referencing (geometry) is also much more straitforeward I think. Just wire it in to something else and you have an instance or reference. With expressions I really like how Houdini doesn't need dialogs to make parameter wires, just type whatever in, it can pretty much reference anything .. just watch out for dependencies but it will even let you know when that happens (view dependencies).

cluster = transform / softTransform ( to get the pointWeights going, take a look at attribCreate and paint SOP and to use the point attribs data along with the softTransformSOP look at the “point” expression command, in general there are many ways of doing this, but this is the closest one to what you are used in Maya )

freezeTransform = the very top UI element of every objectOP, it's called “Pre-Transform”, pay attention and to the other element next to it “Keep position when parenting”, luckilly this one is not that destructive as the freezeTransform thing in Maya.

goalPP - nope, no dynamic goals for you in Houdini, you can cheat to some point with pointSOPs, expressions or chops tho.

particleID = that's the ID attribute which comes by default with every particle ( for more info - RMB over any OP in Houdini - spreadsheet ). You will find the expressions quite dissapointing, but stay tuned, the upcoming version comes with python stuff, so in most cases it will get much better. Also, some expression commands are really great geometry iterators. For this kind of stuff in Maya i am forced to do API exercises to keep some reasonable performance :?

snapping - ctrl+j and ctrl+shift+j

blendshape snapshot - what you mean ?

constraints: *origin expressions + blendOP can do point orient scale constraining, blendOP to get the transformation in local space, then *origin expressions to pull them in world space so that data can be usefull. Every objectOP has built in aim constraining abilities to some level.

polyAverage = smoothSOP

Have fun.

blendshape snapshot

Would that be like locking a sop, or writing the geometry out with a rop and reading it back with a file sop?

I would read that as a saved pose.

Simon
blendshape snapshot

Would that be like locking a sop, or writing the geometry out with a rop and reading it back with a file sop?

to procedurally take a “snapshot” you can always read the animated geometry into chops at that frame, then output it back to the mesh in a different tree

Not sure what “goalPP” does, but in Houdini you can use the Follow POP (used for Flocking) and set the Leader to “Individual Particles” so you can have 500 particles go to the 500 vertices on an animated surface for example.

-Craig

Thanks for all replies. I had a few days to dig into docs and the replies really helped. Really, thanks. I guess maya and houdini is like translating spanish and english, some things are almost the same, other things don't work the same way at all, but all mean the same thing.

Last thing. Is this a vex thing I describe? Just so I know so I can leave it for a later stage of my on-the-job-learnings ;

I have an object. I can use add sops and point sops to keep just the points that inherit shading normals from the original object, in preparation for adding sprites to the points as particles that use those normals for lighting. All ok until I add sprites and then I lose normals and just get a default normal facing the camera. And I cannot see how I can stop this behaviour. I am not a really, really technical user so going into vex at this stage is too early for me, I know how to do a similar thing in maya because I used the software a long time - that method I would make softbody object, add a mel expression in particle node to inherit normal orientation, then throw away underlying object to just leave particle cloud with original normals ready for lighting. Is there a way I can inherit normal directions directly in my houdini scenes?

Thnk u,