Lamp shades

[SeanOSkea]

Hello all:

I'm working an a new show with a lot of onstage practicals--various lamps and such. I'm trying hard to match the quality of light in the attached reference photo. The other attachment is where I'm at. I've been messing with: Glow or back light on the shade, a point light inside the shade with various levels of transparency on the shade's texture. I've tried Fresnel on the shade. Just about everything. In this snap I have an overhead spotlight to cast the light on the floor.

When the Shade looks good, everything around it is dark and dingy. It looks like the lamp has a 20w bulb in it. But when enough light is being generated to look like the lamp is giving off a normal amount of light the shade is just blown out all to heck like it is here. I'm at the point of just doing multiple renders and patching then together in PS.

But before I do has anyone come up with a good lampshade solution?

Curious to hear.

Sean

Edited August 12, 2016 by SeanOSkea

[zoomer]

There is an example in the second half of the video :

[rDesign]

Sean-

In the Reflectivity channel of your RW texture, use a Backlight shader. You can control the amount of glow from the bulb by changing the Brightness of the Backlight shader. You don't need to set any transparency.

See the attached VW2016 file.

[AlanW]

Hi,

I tend to use a glow texture to produce the light source, its more efficient on the computer power than using lights.

You can turn of the render for the light bulb so you don't see the solid.

If you look in the resource browser you will see a texture called Glow, just change the intensity up and down, say 500 min 2500 max.

If you want a lot of lights I would create a few and name it Glow_800, Glow 1000 etc so you don't have to keep changing the texture as it will change all the lights.

Needs to be rendered in renderworks style and I have one in the file called Realistic Exterior Fast that I have set up for my own purpose that seems to give a realistic appearance.

I have ambient light turned off in these pics.

Last image i turned Ambient light on but only low level at 16% and turned on Ambient Occlusion on.

File available at

https://www.dropbox.com/s/wsw086ucsfm6vj8/Lamp%20%26%20Glow.zip?dl=0

HTH

Edited August 12, 2016 by Alan Woodwell

[SeanOSkea]

Thank you everybody. I'm eager to give these a go.

Sean

[SeanOSkea]

Thanks Alan. This is close to what I was doing but your settings are better. Thanks. I'm curious about what you meant by "You can turn off the render for the light bulb so you don't see the solid"

Sean

Edited August 13, 2016 by SeanOSkea

[SeanOSkea]

Well in practice its still not what I need. Tim's low-powered backlight-only version makes the shade look good but doesn't emit anywhere near enough light to suggest that the lamp is actually lighting the scene. My settings were already close to what Alan had with the glow texture on bulb and a transparency to let the light out. But Alan's scene is lit by the HDRI. The lamp looks great but again the suggestion of the source of the light coming from the lamp itself is not there. I've played with point lights inside or just above the lamp like in the video Zoomer attached but it drastically increased render times with only slight improvements in the result.

So I'm kind of back to where I started. Thank you all for the quick replies I'll post whatever I end up with.

Sean

[SeanOSkea]

Well I'm still not totally happy but this one looks a bet more like what I was after. This has a point light just above the shade with soft shadows and Realistic falloff. It has a slightly yellow color and is set to 160% Brightness.

The shade has backlight set to 80%.

I couldn't get a transparency setting with a glow texture that didn't look odd.

I'll keep playing.

Sean

[AlanW]

Sean, "You can turn off the render for the light bulb so you don't see the solid.

Cant remember where it is but you untick a box that says don't render geometry so you only get a glow and not an object. Cant find it now.

I'll keep looking

Sean, The problem I found was getting the overall lighting levels down, then I remembered that if i put a real light in the ambient level hit real low. So Have added a transparency to the glow texture, added a spotlight out over the back of the scene which dropped all to black and rendered and got this. Put the light on a separate class so you can turn the class off so you can see the drawing otherwise its all black.

Still all done with glow textures.

HTH

File at dropbox

https://www.dropbox.com/s/dhkgyf2h968onmj/Lamp%20%26%20Glow%20%282%29.zip?dl=0

Edited August 13, 2016 by Alan Woodwell

[rDesign]

Sean, "You can turn off the render for the light bulb so you don't see the solid.

Cant remember where it is but you untick a box that says don't render geometry so you only get a glow and not an object. Cant find it now.

I'll keep looking

Alan - maybe you were thinking of on the Light Source properties OIP there is a check box for 'Render Geometry', but that is used for area and line lights and not for Glow textures.

One thing I noticed in your initial sample images is that the glow texture illumination from the lamp shades is not being reflected in the glossy wall behind and it just doesn't look quite right. (Maybe it's a function of the max number of reflections in the Custom Renderworks options).

[SeanOSkea]

Yeah I got excited for a moment. I know you can hide objects from the render camera in C4D and others with the tick of a box. I thought is that possible in VW too and I've missed it all these years!?

That would be awesomely powerful. create a 1-sided NURBS ring with the normals on the outside and then apply a glow texture to it. Put the ring around the lamp shade, hide it from the camera and bam! That would be perfect.

Oh well, another one for the new features wish list.

Sean

[rDesign]

Well in practice its still not what I need. Tim's low-powered backlight-only version makes the shade look good but doesn't emit anywhere near enough light to suggest that the lamp is actually lighting the scene.

Sean - do you have Indirect Lighting turned on and Ambient turned off ? View > Set Lighting Options.

In my attached FQRW image, I have Indirect set to 4 Bounces, Ambient is turned off, no HDRI lighting — I think the amount of light from the 4 lights is pretty believable for a 20' by 20' space.

Three of the Lights are set to 75% brightness, one is at 90% (just for kicks). The Lights themselves are slightly above the vertical midpoint of the lamp shades.

Personally, I haven't had much luck using Alan's recommended Glow textures technique on floor lamps like these where you see the bulb: I tend to use Glow textures only for recessed linear fluorescent fixtures. For me it takes more time to tweak the transparent Glow textures than just using a light and a backlit texture. Yes, it will render more slowly, but the lighting / texture setup is much simpler.

My simple test image above (Sheet Layer Viewport at 150ppi) still rendered in 1.5 minutes, which I don't think is that bad.

[SeanOSkea]

Tim:

First question, how are you embedding your images into the body of your posts like that? That's great.

I've played with both settings but I've kept Ambient on at about 10% just to keep Occlusion on.

I do have the settings just about how you have it. As it's for a set design, the effect I'm going for is small pools of light on an otherwise dark black stage.

Looks like you are doing here close what I ended up with. I put the light slightly above the shade and set it to realistic falloff so I could get the short throw glow that I need. I could see putting the light obj low for a higher shade like your floor lamps here.

I think this is going to work for me it's just taken a lot of fussing to get everything balanced.

Thanks,

Sean

[zoomer]

Tim:

First question, how are you embedding your images into the body of your posts like that? That's great.

1. Attach/upload images

2. Write message

3. Submit post

4. In your own post, open attachment in new window

5. Copy URL to clipboard

6. Edit your own message

7. Icon "Enter an Image"

8. Choose "Insert a non Floating Image" (Other options won't work)

9. Enter your URL from clipboard

10. Press OK

11. Save edited message

[rDesign]

Thankfully — in the very near future when the new forum site launches we'll no longer have to do what Zoomer described, as we'll be able to drag-and-drop images directly into our posts. It'll be much easier.