Cylindrical Light Source?

[daveh777]

I've also just tried area light under MR but that gives me either a point light or spot light. Not really having much luck, just bumbling around :)

Dave

[T-R]

Well I think your on the right track. A mental ray area light will work. Just change the 'type' to cylinder and scale it to match your light source. Up the sampling from 3,3 to maybe 6,6 or higher when its final render time. You can also give your object a incandesnse colour, then turn off the default light and turn on final gather and then the object will emit light. You will then have to take the steps to clean your FG up. Oooorrrr you can do a search in the maya rendering forum for Ctrl Object lights. This is a great tool by francescaluce that will convert any object no matter what the shape to an area light. The first soloution should work though if your object is just has a cylindrical shape.
see the attached pic for a quick test with the 1st method.


http://img216.imageshack.us/img216/7508/light6uc.jpg
(http://img216.imageshack.us/my.php?image=light6uc.jpg)

[daveh777]

Hi T_R,

thanks for your great response and pic.

I'm a tad confused though, please bare with me...

I created a cude then removed a face.
I put a point light inside the cube.
I render test1 using MR.
I then turn the light to an area light and change the shape to cylinder. No difference what so ever from the test1 render.
I increase the length of the area light by using the scale transform tool.
I render again and again there's no difference.
I adjust the sampling to 6,6 and again no difference.
I turn on final Gather this time I see a little difference but not much.

As you can tell I'm a total newb to maya.

you pic is great, can you tell me please the steps you took to create it in a more detailed fashion.

thanks again
Dave

[daveh777]

especially the transparent bit's at the end and the shadow effect from the end of the cylinder.

[daveh777]

sorry to be a pest.

[T-R]

well heres a scene file:)

[GennadiyKorol]

Try the volume light, just set it's shape to be a cylinder. Here's what I've got with a quick test (maya renderer, 0.06 seconds):

[daveh777]

Hi lads,

thanks for your help and effort with this, I appreciatte your time.

but I still can't see what I'm looking for. I thought if you render a cylinder which emits light from the entire length of the cylinder would look completely different from a single point light. Here's an example I've drawn up in photoshop that sort of explains what I think is the right way of light to be displayed by a cylinder (test5.jpg). It might not be, please let me know if I'm talking a load of rubbish.

I've also attached a pic that shows that there's hardly any difference between the light emited from a single point and a area light or volume light (test4.jpg).

let me know what you think?

Dave

[Emil3d]

Hi Dave,
I would never imagine that a light source with that shape in the middle of a room will produce a white strip on one of the walls like the one on your second image. That would be a case if it is a spot light with such shape, directed at the wall.
A cylindrical light source has the same effect as a row of point lights

Anyway you can still easily achieve that in Maya by simply moving and resizing the volume light cylinder to overlap and fit the lit area on the wall . Have in mind though that the volume light illuminates only within the volume of its icon. You will need another light or other tricks to show the rest of the room.

Why don’t you describe what kind of imagery and actions you scene is suppose to achieve? You may get more help by describing your final goal. For example if all you need is just that simple image you showed, you can achieve this without the use of any lights just by mapping a ramp shader to the ambience of the walls and putting a cylindrical object in the middle of the room with incandescent material and glow.

[daveh777]

Hi Emil3d,

I'm basically trying to learn how to use Maya. I've experience from a long time ago using programs such as Imagine and Real 3D on the Amiga. Yes I know, that was at the same time they were burying the egytians in tall pointy buildings.

So I'm trying to break down all the different parts of Maya and learn each one, i.e. the lights in this case. I was wrong to think a light cylinder would look like that. I must admit it's hard for me to try and visulaize lighting in my mind. Is there any good sources on the web that helps with lighting examples?

I'm off to try and learn FG and GI now, oh oh, should be fun!

cheers to everyone for the help
Dave

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