hey …

Today i wanted to do some light instancing in Houdini 10 but i can't figure out how this is working. I searched the forum and finally found a video tut about this subject that was done in Houdini6, but i can't apply the technique to my houdini 10 version.


In fact the shader SOP (that was used in the tutorial) in my scene doesn't work at all, it gives the following warning
“this SOP is deprecated in favour of the material SOP”.
even if i turn on “generate point attributes for instancing” and chose a light shader in the “lightshaders/light” tab it won't work.

ah and of course i told plugged my geometry into an instance node and enabled “point instancing” also chose the light as the instance object.

it would be great to get a hip file how light instancing can be done or a quick walkthrough, that would be very nice of you advanced houdini users )

well wish you a good night,

Manuel

ok guys!
then i will provide the answer myself

if your center ist say at 5,5,5 you can zero it by writing the following simple expression:
$TX - $CEX , $TY - $CEY , $TZ - $CEZ
in the position value of a transform SOP !

maybe it helps someone,

cheers

hi everyone!

i found the solution to the problem, the copysop can't handle primitive points so ein used the $PT variable and and a rand() expression to stamp the primitives into my copy SOP.

Now i am really confused because the copy SOP distributes the primitives randomly in space, they're not sticking to the provided template points.

I used a transform SOP to center the pivot of each primitve ($CEX,$CEY,$CEZ) but that doesn't work.

I would really appreciate some help, please take a look at the hipfile!

thanks a lot, greetings,
Manu

hey folks,

sry to bump into this thread, but i have a similar problem ))
i followed the “Creep Tool With Copy Stamping” Tutorial of the sidefx website. I created those different colored pebbles and put them in a partion SOP to create a different group of each pebble (rock_$PR).

Now i want to assign these pebbles to a new template. Say i have a grid with 9 points in it so i would need exactly 9 of those pebbles. Obviously i have to use the copy SOP but i can't solve the problem with the switch SOP method because all my primitves are in ONE node.

Can anyboy help me please?? )

best regards,

Manu

ps. sry Eugenerockstar for interfering

hey Peter,

i already enjoyed a lot of your tutorials, they're awsome and
fast forward, i like that!
I wonder where you got your knowledge about Houdini ?!

with the best regards,

Manuel

well, i must agree, some lessons really don't work out in the end, like in the first one with the static object node, i could not find out why the constant fluid emission doesn't work in houdini 10 :?

got it
again, thx for the help buddy )))

tamte
if you are using Inherit Velocity for particles you need either normals “N” attribute or velocity “v” attribute on your source geometry

since that Point SOP creates both, you can left one of them off

i recommend you to set normals to Keep Normals
and velocity to Add Velocity with values $NX, $NY, $NZ

this way the source geometry will have only “v” attribute for particles to inherit velocity from

particles will have no “N” attribute, so the copied objects will be aligned with velocity

one last thing, after that let's call it a day )
didn't you mean “Add Velocity with values $VX, $VY, $VZ” ??? :?

thx a lot mate!! really nice of you!
and well … i'm not scared, en contraire i'm looking forward to learn this software although there will be a lot i wont understand straightaway, i'm new to expressions and maths ))
lets see first i have to go through all those example files and try to get an overview to all those nodes and expressions and then … i'm psyched of the possibilites houdini provides, before i used 3DS Max and compared with that, Houdini is a whole new experience …

cheers!

btw Tamte, where can i learn more about those attributes you talked about? like “N”, “ROT” “ORIENT” etc. ???

of course! thx anyway for the advice.
But hmm the more i contemplate about ragupastas example — why did he put this channel expression in the particle velocity attribute of the point node? doesn't make sense to me and if i switch it off, nothing happens, the whole thing is still intact?!

thx a lot guys, that's exactly what i was looking for!
I didn't create an “add velocity” (ch(“nx”)) in the particle rollout of the point SOP in the first place, i guess that was fault nr.1?? then i didn't orientate my object to the z-axis in world space, i guess that was my second.

but hmm Tamte, the stuff you're telling me, it's a little confusing I'm new to houdini. I basically know that one can create attributes for the particles and access them on the geometry level, but that's about all i know. It's definitely a field that i want to learn more about. Has the stuff you told me something to do with the attribute node or else with the attribute rollout of the copy node?

hello,

i've got a little issue here, been trying and trying but can't figure out a solution, i guess it's not complicated, i just don't get it

here's the thing. I created a sphere and added normals to each point with a point SOP. Then i connected a POPNET to it and emitted a particle for each point and let it fly in the normal direction of the points. (attributes>velocity>$NX, $NY, $NZ)

Next i created a cylinder. Through the copy node i wanted to align a cylinder to each emitted particle's velocity direction. How can i achieve this?

some help would be appreciated,
thx & with the best regards,

Manu