If you map the 2D picture onto a plane, the spotlight will light it’s surface, but it obviously won’t interact in any way with the detail within the 2D picture, so you can’t for example alter the light direction within the 2D picture, only light the whole surface of it.
If you use a 2D face to hold a photograph you wish to use as a backdrop, for example, you can light it with a spot. Make sure you have shadow casting, self shadows and receive shadows in the materials option deselected. You can also use the light in the back of the 2D face and set it to ranged so the light doesn’t interfere with the 3D objects in the scene.
Best option would be to use a parallel light (instead of a spot) without shadows and include only the 2D face. Objects lit or not lit can be included or excluded for any light in the light lab.
Thanks to you both, I will have to have a play around with that. I want to put a picture of the moon in one of my scenes but it isn’t very bright & I would like it to be a bit more prominent so thought using a spotlight on the front face would make it stand out a bit more.
Well depending on what the finished result is going to be, as the default picture in the Mat Lab is the Moon, it took me no more than 15 minutes to make the picture below.
First create a 2D disc (it’s under the little gold man’s right foot on the tool shelf).
Then with the disc selected go to EDIT and click the Mat Lab (the first button on the shelf that looks like a block with a chunk missing from it).
Next to the line that says “diffuse” there is a grey oval showing the default diffuse colour. you need to drop a ball into the first row of the blank dimples to it’s right. You do this simply by clicking on the dimple.
To the right again you will see a new box has appeared where the ‘A’ was.
Click the ‘P’ button in that box. This allows you to select a picture to use as the diffuse colour.
It usually put the gold man in the little preview at this point.
Now click the little round button on the top row directly above the ‘P’ button to enter the ‘Picture Source Editor’.
Click the picture of the Moon and it will load into the top squares.
Click the tick to return to the Mat Lab.
In that same little nested window just tot eh right of the ‘P’ button is a similar button but with an inverted triangle on it.
Click on this to reveal a drop down menu.
Select “Object Cubic” and then click the tick (bottom right).
There should now be a picture of the Moon on your 2D disc, which you can rotate to face the camera and position where you need it.
To light it up, all I did was to group it along with a regular radial light, set to exclude everything except the disc. Grouping it is just to make it easier to reposition if necessary. Then set your scene and light it to match making sure your other lights exclude the disc and light group.
Yes, the light is set to only affect the 2D disc, but then when the 2D disc is lit up, it will reflect like any other visible object in a reflective surface. The only thing you have to do to make it look as genuine as possible, is to make the moon and the light group really big and move it quite a long away from the camera. Otherwise the reflection will not look like it starts at the horizon. This also has the advantage of allowing the moon disc to be affected by atmospheric conditions you have set such as haze/fog.
You can’t really tell in that first picture but I also put a layer of cloud between the moon and the camera, it shows a bit better in the pic attached to this post. Using volumetric clouds, you can get some great moon behind the clouds effects, but I just used a surface cloud, not a volumetric one (it makes rendering a lot quicker and can do the job in some instances).
Brilliant & thanks a lot, that’s just the info I wanted. Some of the stuff in Bryce I find way too complicated to understand at the mo but that makes complete sense. I’m more used to working in 2D as a more traditional artist & thinking in 3D makes my brain ache but I’m determined to learn.
If you use an HDRI sky (in the IBL sky lab tab) you can exclude the 2D disc from the effect, then you can set up a light close to the disc and use the light lab editor to only include the Disc so that the (new) light doesn’t spill light into your scene.
It looks quite natural as you have it at the moment though. It certainly doesn’t look wrong.
Thanks for that, yeah I quite like the effect as it turned out but def want to do some full disk work in the future & it will bug the hell out of me if I don’t figure it out so that may be the solution, though HDRI is a bit of a mystery to me at the mo, need to read up on the excellent tuts we have on this site