View Full Version : Problems with Volumetric lighting

03-22-2012, 07:17 AM
I have had quirky problems with Volumetric lighting off and on for years, but this one is strange. While we are on the subject, I have had similar problems with HVEs too. The crux of the difficulty is in parenting these items (Volumetric lights and HVE's) to other objects. When I do it seems that the properties change drastically. In this morning's problem, I have a volumetric light that works fine. However, I need it to move when this roach wearing a headlamp moves his head. So I parent it to his head layer, and suddenly the Vol Light will not render. I can unparent it and it works fine. So I parent it to a bone near the head, same deal. I had noticed before that when I parent a HVE to something, it no longer produces particles. So I thought, this can't be true, maybe I need to do something else. SO I parent a null to the object and then parent the VolLight to that null, same disappearance of my light beam. This is messed up...any ideas??

03-22-2012, 07:38 AM
I see what was happening, and I thought this might be the case. Still doesn't explain it.


You see the framing I wanted...no beam. If I move the camera WAY back, you can see the beam, but it
acts as if I had much different settings for the cone base and height. It acts as if they have moved far out,
but the cone base and height are set at about what you would want for a realiztic beam from the head of that roach.
I guess I have no choice but to try an offset, but then what is the use of having the colored indicator lines that show you
where your beam begins and ends? I admit, I am using LW7, but this is dumb for such a smart program. Maybe I am the dumb one.


03-22-2012, 09:00 AM
If I remove the geometry that would block any light rays, i.e. the back of the spotlight and the front of the lens, etc., I can get the light to pass through as a volumetric light beam. If I parent it to the head of the roach, SAME position and geometry, the beam "goes away" But in reality, it didn't go away, it simply grows by a factor of 5-10 and shows up way off-camera as shown in the second photo above....What a load of BS....thanks Lightwave.


03-22-2012, 09:04 AM
Hmmm... no clue... it SHOULD work. I, infact, remember doing much this exact same thing years ago, with a character holding a flashlight. Now I was (and Im certain) doing this in V7.5 at the time, so maybe its a bug in 7.0. Perhaps you should get the 7.5 update (which if u have 7 ur eligible for) and see if that makes a difference.

The other thing you could try, to get away from DIRECT parenting, is to constrain the light to where u want it. You can do this in 7x in a couple of ways. First thing is to create a null, parented to the bone in question, and then either use the parenter motion modifier, OR simple position and orient constraint modifiers to them "stick" the light to this null.

Edit... oh, just saw ur 3rd post... so it DOES work, but the beam is in the "wrong place".

Perhaps LWs just not picking up the position of the light itself as per its parent relationship... in which case you may need to "bake" the motions of your character rig (motion baker)... or, again... go for 7.5


03-22-2012, 09:26 AM
To me it's kind of like what happens when you have a multi-layered object with bones.
And maybe this will tell the tale. Do you ever have a character in a scene, and you turn
skelegons into bones on the body, and then parent the arms to a bone and the arm goes
flying off to the right and out of orientation? And you have to move the arm BACK into
position and create a keyframe for it to stay in the proper orientation? If you answered NO
to these questions, then yes, I need a better copy of LW, lol. I just hate to reward Newtek
with another purchase when everything I ever got from them came with a hassle. Have you
ever had one of their dongles work out of the box?? Of course not. You always have to call
and work through it on the phone. Same with their Tricaster and all three copies of LW I have
ever bought for myself or for work.

Thanks for your thoughtful reply.

03-22-2012, 09:54 AM
Yes, I have had Every Dongle work out of the box with Lightwave....... Of course, I had to go through the Registration page of Newtek for the Key and such, but that is a normal step or process.

03-22-2012, 10:05 AM
Ive still got the same dongle I got with 7.5 purchase, worked first time and ever since... I did once have a knackered disc for V8, and after requesting a replacements I got... a VT3 disc!

But if it is a 7.0 bug thats fixed in 7.5 you dont have to pay to get it... the .5 upgrade is free to you, and should be available in your registration downloads.