8 replies to this topic

[hopbin9]

Hi,

I'm kind of stuck on coming up with a practical approach to doing lightning in Houdini. I need to generate the lightning effect as a point to point solution. So that I can have the lightning travel between different objects.

In the Houdini manual it says a L-System can be used to create lightning effects, but it doesn't give an example. I tried to play around with l-systems but I could only get it to grow lines from a source point and not to a target point. I've searched this forum, the Sidefx forums, Google searched, Youtube and Vimeo. Can't seem to find a tutorial on lightning in Houdini anywhere. cmiVFX has some training DVDs I might order that cover l-systems, but I can confirm that they cover the topics of lightning.

Can anyone point me in the right direction?

Thanks,

[hopbin9]

Oh, so there is a lightning preset for l-systems. Wow, been using Houdini for a few months and never knew there were presents. Thanks sidefx for making that feature so easy to find.

Can anyone tell me if it's possible to make the lightning target a point?

Thanks

[Rudinie]

Lightning from point to point is explained in a cmivfx-tutorial called "Houdini Procedural Animation Techniques".
Check it out, it's not free but you will learn more then just the effect you're searching for.
No, i am in no way related to cmi-vfx. :-)

[anim]

i believe that cmiVFX lightning from that DVD covers only curve based lightning, not branching one (at least what is seen in trailer video)

here is an example of creating simple 2 point lighting based on l-system lightning preset
it doesn't have up-vector so it may flip at some time when animating points and it's scaling the lightning to match points distance, it's not increasing in length
just to keep it simple as an example
it all depends on what you want

you can completely avoid l-systems
create line between 2 points
resample
add some noise to middle part
copy some noise lines onto it and maybe in more generations to recreate complex branching
this may provide you more freedom than l-systems

Attached Files

•  2_point_lightning.hip   96.8K   279 downloads

Edited by anim, 04 January 2011 - 02:07 PM.

[hopbin9]

Thanks guys,

That scaled lightning might be just what I needed. Thanks

I'm going to take a look at the cmiVFX training DVDs.

[hopbin9]

Hi,

I figured out a way to get lightning to follow a two point line. See attached.

Found an old copy of the Houdini 8 manual on sidefx.com that references using the Rails SOP to scale/orient an l-system, but it looks like the tutorial was never finished.

Lightning Letters

This approach is nice cause it's a little easier to understand , but I want to now make curved lightning. Maybe using the Project SOP to have the lightning wrap around a Tube or something.

Attached Files

•  lightning.hip   86.91K   200 downloads

[Ankit Sinha]

anim, on 04 January 2011 - 02:06 PM, said:

i believe that cmiVFX lightning from that DVD covers only curve based lightning, not branching one (at least what is seen in trailer video)

here is an example of creating simple 2 point lighting based on l-system lightning preset
it doesn't have up-vector so it may flip at some time when animating points and it's scaling the lightning to match points distance, it's not increasing in length
just to keep it simple as an example
it all depends on what you want

you can completely avoid l-systems
create line between 2 points
resample
add some noise to middle part
copy some noise lines onto it and maybe in more generations to recreate complex branching
this may provide you more freedom than l-systems

can you tell with help of what parameter i can make it like approaching from one point to other one, in your this example file? I have figured out few ways but i am not sure if its right way(efficient and fail proof way) to do that....

[anim]

the easiest way is to utilize arc attribute coming from L-System, which measures distance from origin, so you can use it to delete points based on that distance and therefore make it grow or shrink

Attached Files

•  2_point_lightning_growing.hip   121.42K   73 downloads

[Mr. Green]

I am still a relative beginner in Houdini, but I recently learned how to make a procedural lightning field from a tutorial I bought recently.  Basically, the gist is you can create a lightning bolt from moving objects that reach to the nearest point on another object within a specified distance.

You can see the effect in this video I made.  I am going to expand on this technique beyond what the tutorial taught me, but it was a really great lesson and I'm happy to share it with others.  Once you understand how this effect is made it's easy to see how scalable it is and how to apply it to other objects (ie...a spaceship's landing gear contacting the ground or something).

Vimeo: Lightning Field

Attached Files

•  boltdrones_005.hip   240.9K   305 downloads