getting propper Rays in Fog Cone / VrayEnviromentFog

[caypiranha]

Hi Guys,

I am wondering how to get a correct volume effect like the example picture here. Having a movie sequence, that should give crisp and clear visible rays onto the light cone.
I used a vog gizmo (actually a polygon Cone) and the spotlight which has the source film in the texture slot. But it doesn´t affect the cone that much (the spotlight is in the Fog nodes as well)

Thank you very much in advance for any Hints! (Yes, I know, that doing these stuff in Compositing is also great, but no time to learn it now... =)

My result so far and the other is the one is what I am looking for:

[fixeighted]

You can use a regular Max spotlight with Vray shadows and your 'movie' in the projector slot.
You will need a box gizmo for the fog, constrained (for speed) around where you need it to show, rather than using your current cone as the gizmo.
Just play with the fog parameters to get something good but to start, leave emission off, Scatter GI off.
This setup has the benefit of actually being able to project your film onto a screen if you so desire, if you set it as a rectangle light

[caypiranha]

thank you very much for the details!
I found by chance also that the good old Fspot made the Job. I used the Atmosphere&Effects Section down at the Fspot attributes, where I used a Volumen Light to get the Fog.
It is working not that bad at all, but I see sometimes, lot´s of repetitions from the movie along the Cone. A bit wired, but with Noise and Falloffs, it´s ok for now.

I understand, that you use still VrayEnviromentFog together with a Fspot? What do you mean with the "box gizmo constrained for speed" ?

I´ll try it... =)

[fixeighted]

Glad you found the solution.
With the gizmo I just meant to make it as small as possible around the 'cone' to save on calculations, if that was an issue, though it's pretty fast so likely not a problem anyway.

[caypiranha]

Understand.
I recognized, that the poly cone used as a gizmo, roughly around the spotlight, it was speeding up even more than a box.
With the Fspot, I even don't need a Gizmo now at all. Chosen under the Spotlight´s Volume Light Effect in the Environment Tab seems to contain this automatically and fits with autom. with spotlights angle..pretty cool...
but I am missing a way to give more steps since the pixel content plugged into the light, gives repetitions all along.

The beams now are having interrupted Lines:

[^Lele^]

attached .

[caypiranha]

thanks Lele! .. but where did you plug the texture inside? in Atmosphere is your Maps tab closed. But when I plug something inside, nothing happens really corresponding to the bitmap

[^Lele^]

There is no texture in the fog as such. There's a texture as projector in the spotlight.
And i have *no* idea why it doesn't show up in the attributes for the light in my screenshot, either! (edit: reloading the file showed it.)
So, put it into the projector map section of the spot.
Hot tip: use the vraybitmap multiplier/CC to have more visible rays, instead of fiddling with the fog parameters, much harder to control.
It can go well above 1.0float, thereby greatly increasing contrast (see in my map, f.e.).

[caypiranha]

.. yes, I thought somebody is pulling my legs...!
No, of course not - guessing something unlikely going on the screen.. some kind of usual suspects etc...

The best is, I am having the same here as well ---> hit render, and the connection appears - if you stop it, it will remain as "none" ... yes, perfect !

the nasty thing is, I tried it, but it was crashing instantly....but haven't tried it a second time - like now and it works


... anyways - thanks at all! =)

[^Lele^]

So i duly went trying to repro the behavior, trying to see if it could be us, or it's the spotlight.
And of course, the behaviour*never* reappeared. -.-'

EDIT: ok, found it, and bug reported. Whether it's us or not, i have no idea, but it happens only when one stops an IPR session with the stop button in the VFB. Offline rendering, or IPR running to completion, are just fine.
Also, the bug is *cosmetic only* the map isn't in fact removed from the slot.
Reselecting the light shows the map in place.

[caypiranha]

=D "Dulyness", is what the Program´s just waiting for fooling you...

So, exactly, same here! Only in IPR mode.
And it crashes from time to time, while plying in the SPotlight parameters around.
Right-click under the Projector mapping slot -> open in SME isn´t working here.

But I guess, that might not be Vray´s Problem - more or less it goes to AD ... their Codeorganization must be horrible to control after all these Years of changing Owners and Programmers.

[^Lele^]

We do not have access to all the inner working of Max, of course, but we can investigate.
I have reported the visual bug, will add your report as well, perhaps something can be done, i wouldn't know.

[^Lele^]

Right-click under the Projector mapping slot -> open in SME isn´t working here.

This works for me.
I do not see the map in the main window, but the UI is loaded properly, which seems to be the same behaviour regardless of map class (i.e. a checker works the same as a vrayBitmap).