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Emmitters, Multilight and SL

Posted: Thu May 22, 2008 10:37 pm
by Edward1986
Hi,

I am a fairly new maxwell user and I am just wondering about Multilight.

Do renders with Multilight enabled and with emmitters take longer to render? The ones I am doing with these things involved seem to take longer for the noise to go away and SL's take much longer.

Is this normal?

Thanks,

Ed.

P.s This is my first post- this forum is v helpful!!! :D

Posted: Thu May 22, 2008 10:50 pm
by Mihai
With multi light enabled it won't take longer, it may seem that way because if you have many emitter sliders, MXCL needs more memory (more sliders>more memory) and your computer might be getting to the swap disk instead of keeping everything in ram which will make the render much slower.

You can try merging some of the emitters, so you get less sliders in MXCL. How much ram do you have and at what resolution are you rendering?

Posted: Thu May 22, 2008 10:56 pm
by Edward1986
Hi, Cheers for quick reply,

1340 x 801 is the resolution and I have 2GB of RAM.

At the moment I have had a render going for 1hr 50 and its only at SL 7.6- The scene has 2 emmitters.

P.s. How do you merge emmitters? I am new to this game, very new!!

Posted: Thu May 22, 2008 11:21 pm
by Mihai
You can merge the geometry in Rhino, so it's exported as just one object. Just take care to double the original emitter power in this case, since the area of emission has doubled.

It should be enough with just two emitters. What is the comparison without multi light enabled, and how much free memory do you have left while rendering? At that resolution it should really be no problem....

Posted: Thu May 22, 2008 11:35 pm
by Edward1986
Forgive my ignorance... how do I merge the two emmitters geometry?

I think it is more the emmitters causing the slow down as opposed to multilight. When I do renders with no emmitters they are resonably fast- arond 1hr. How long should a render with a few emmitters and multilight take (basic scene- jewellery)? or is that a 'how long is a piece of string?' type question!

Posted: Fri May 23, 2008 12:03 am
by Edward1986
P.s. One more thing... if I have Multilight enabled can I wait until the scene has rendered and then play about with the lighting without losing any image quality?

Ed

Posted: Fri May 23, 2008 1:21 am
by polynurb
Edward1986 wrote:Forgive my ignorance... how do I merge the two emmitters geometry?
your emitters should be mesh planes built from only two triangles, you can select severaly meshes and use the _join command to merge them even when they do not touch each other. they should show up as a single emitter in mxcl.

Posted: Fri May 23, 2008 1:23 am
by ivox3
Edward1986 wrote:P.s. One more thing... if I have Multilight enabled can I wait until the scene has rendered and then play about with the lighting without losing any image quality?

Ed
Yes with no quality loss. But ! ..there is a scenario when you combine standard emitters and hdr emitters/ mxi .. which you would notice that sliding off the standard emitters and using only HDR -- that there's different in levels of noise (and vice versa for different scenarios).

Your probably a little bit away from this, ..but I thought I'd mention it.

Posted: Fri May 23, 2008 1:23 am
by JDHill
Hi Ed,

To merge the emitter geometry, if it is NURBs, you can use main menu > Mesh > From NURBs Object to get meshes, then use the Join command on them. If you created them as meshes in the first place (I usually do that for emitters, since you have better control over how the mesh is created), then you'd just use Join. So you will end up with one mesh, though it has multiple pieces.

As to changing ML after you're done rendering, yes that's generally the idea. If you turn off all but one light, then you may percieve that you have 'lost image quality', since you are basically excluding a bunch of work your CPU did, in the form of the contribution of the other now-turned-off lights in the scene.

JD

Posted: Fri May 23, 2008 1:27 am
by ivox3
Maybe too much info too fast for Ed ..... :lol:

Posted: Fri May 23, 2008 1:38 am
by JDHill
:lol:

Posted: Fri May 23, 2008 1:42 am
by ivox3
hehe ...

The funny thing is is that me, you and polynurb were all writing the exact same response at the exact same time about joining emitters except I had a sinking suspicion and double checked, ..then backed off. :lol:

Posted: Fri May 23, 2008 4:41 am
by Edward1986
Thanks for the help.

I'll be up to skratch soon enough :D

Posted: Sun May 25, 2008 9:25 pm
by caryjames
Hey Guys: it is me again :).. So JD in Rhino you are creating a plane that you will turn into an emitter then you are turning it into a Mesh?

Is the only benefit to that in the speed at which your computer renders?

I have just recently learned how to apply a colour gradient to an emitter plane to get a nicer render (jewellery) and this is the first I have heard about Mesh emitters.

Thanks guys
Cary

Posted: Sun May 25, 2008 10:18 pm
by JDHill
Hi Cary, I just like the better (simpler) control you have over the mesh when you just create it directly, as opposed to creating a surface and letting Rhino divide it up when it creates the render-mesh.

JD