By andy5000
#390617
I do rather complex interiors ans am wondering what it is the best way to create a spot light emitter in a can / track type fixture?
is it simply create a on sided shape and apply? that is what I have always done and just wondering if that is the best way

This is a pretty opened ended question but one I have struggle with. the first Maxwell tutorial i ever watched used a sphere to create a emitter. It did not explain why a sphere but I assume there is some reason. one having some difficulty before I was instructed to create a cube which is what I typically do . if I have a can light fixture, I place a cube inside it, create a component so I can can control different lights as you would with circuits.
1. Is creating a cube the best way to do this?
2. why was a sphere used in the tutorial?
3. is there any reason to the size of shape for an emitter? say I have a tiny pin hole type fixture, doe it matter if the shape used is one size or another?

I do restaurant interiors for the most part and they end up with a lot of different lights and I always wonder if something I am doing with the lighting is having effects on render times or if there is some better way. Are there fixtures or files that have been created that already have some built-in attributes available somewhere?
By JDHill
#390619
andy5000 wrote:I do rather complex interiors ans am wondering what it is the best way to create a spot light emitter in a can / track type fixture? is it simply create a on sided shape and apply? that is what I have always done and just wondering if that is the best way
Probably the best way would be to create a material using the Spotlight character (Scene Manager > Material > Character), and apply it to a group containing any type of geometry. The type of geometry doesn't matter, because it will be ignored; it is important to use a group though, because its orientation will determine the spotlight's direction. Also keep in mind, when working with the Spotlight material, that you can change Material > Preview > Scene to something like "emitter_spot" to better visualize the changes you are making.
andy5000 wrote:This is a pretty opened ended question but one I have struggle with. the first Maxwell tutorial i ever watched used a sphere to create a emitter. It did not explain why a sphere but I assume there is some reason. one having some difficulty before I was instructed to create a cube which is what I typically do . if I have a can light fixture, I place a cube inside it, create a component so I can can control different lights as you would with circuits.
1. Is creating a cube the best way to do this?
2. why was a sphere used in the tutorial?
3. is there any reason to the size of shape for an emitter? say I have a tiny pin hole type fixture, doe it matter if the shape used is one size or another?
I'm not sure which tutorial this would be, but perhaps it was showing the use of IES files, with which you should usually use a spherical geometry. For other scenarios, just keep in mind that in general, it is preferable to have fewer triangles with emitter material, when possible, and that you should not shine light where it cannot be seen, if you can help it (say, putting a cube inside a the pinhole fixture you mention -- some of the faces of the cube will shine pointlessly on the inside of the fixture, not changing the rendered image, but still costing CPU cycles).
andy5000 wrote:I do restaurant interiors for the most part and they end up with a lot of different lights and I always wonder if something I am doing with the lighting is having effects on render times or if there is some better way. Are there fixtures or files that have been created that already have some built-in attributes available somewhere?
There are various IES files that can be used in emitter materials, but I'm not aware of any ready-made fixtures.
#390828
just keep in mind that in general, it is preferable to have fewer triangles with emitter material, when possible, and that you should not shine light where it cannot be seen, if you can help it (say, putting a cube inside a the pinhole fixture you mention -- some of the faces of the cube will shine pointlessly on the inside of the fixture, not changing the rendered image, but still costing CPU cycles).

ok, thank you for your response. so to create the look of a can fixture without doing this how woudl I do that? if i don't create a can for a fixture I am not sure how to make that work
By JDHill
#390834
I wasn't saying you can't or shouldn't model a can, but more responding to how you suggested it would use a "tiny pinhole"; I am not sure exactly what you meant, but it didn't sound optimal.

I've made can lights before where the body is a cylinder, with a pure black diffuse material assigned, one end of the cylinder is an emitter shining through the cylinder, and the other end (also black, the point being to kill unused light rays as soon as possible) has a circle (with diameter equal to the cylinder radius, say) removed from the middle; by moving the aperture disc toward the emitter end, you can change how the light is focused.

Not sure if that's what you're looking for, but depending on the length you make the cylinder, and the size of the aperture, you can make lights that are however focused (to the point of being like a stage spotlight) you wish.

Or, again, you can use an emitter that uses the Spotlight (or IES) character, and not fuss about with the geometry.
#390838
oh,, thanks. it didn't occur to me that the interior of the "can" color would have an effect like that. so if I want to look of a recessed can fixture or a cylinder first there is no reason to make t deep and it should be colored black on the inside. My render times are super slow (12 hours or more on a complex interior) and I am sure its the way I am doing the lighting and probably other things.
By JDHill
#390840
Yes, it can make a difference, and more, the closer to the emitter source that you get (since a black surface further out in the scene will encounter fewer rays, which may already have bounced a few times to reach it). Since the thing that Maxwell does is calculate how light rays bounce around in a scene, the more you can help it out by killing rays you know won't meaningfully contribute, the better.

But this is always up to you; it would be nice to automatically figure out which rays will end up not contributing, but if you think about it, to do that, you have to calculate where they end up going -- which is exactly what the rendering process is. The only other way is to make assumptions, which cannot be proven to be true, and which would therefore necessarily damage the result, if the goal is to simulate photographic reality.

As far as general optimization, again it involves trying to kill rays that aren't important. Perhaps there is a wall behind the camera; in real life, that is going to have an effect, and it will in Maxwell, too. But, it may that is not important for a particular view, and that you can therefore speed things up by removing or hiding the wall. Because, think of a ray of light that has come from an emitter, bounced off a surface toward the camera, and just missed hitting it; from there, it can either bounce off the wall back into the viewable scene, or go off into space (ending its life), if the wall has been removed. But it is only you, as the artist, who can decide whether this is an optimization you want to make, since for example, there could be a mirror in front of the camera, which would reveal the trick.
By andy5000
#390842
thank you so much. very helpful advice.
the more I learn the more I want to know.
I use the plug in for sketch up and somewhere think I saw that it only uses a single core of my computer. is that true and does the stand alone version render much faster?
By JDHill
#390843
It uses however many threads you specify in the Maxwell FIRE settings (the "gear" button in the FIRE window), where 0 means "use all available threads." There is a separate threads setting for the material preview, in Scene Manager > Options. Maxwell Suite may render a bit faster (it would make no difference inside the plugin), since there is apparently some OS-related overhead to having it working inside of another application.

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Change Grass materials

Nope :wink: