topic Re: Picture object black? in Visualization

Picture object black?

Anonymous — Thu, 11 May 2023 10:23:53 GMT

Hi

Does anyone know why my custom picture shows black when I render? It shows up fine in the 3d window but when I render it the custom picture turns completly black.

Im using v11 and rendering in lightworks. Sun and sky objects and window lights.

Re: Picture object black?

Anonymous — Fri, 21 Dec 2007 20:54:25 GMT

I have the same problem with the Television object.

Re: Picture object black?

Palawat — Sat, 22 Dec 2007 09:03:09 GMT

If you start with internal engine, don't forget to click the "Match Internal" box in lightwork engine.

or maybe you can show us the screen shot of how you set your material.

Re: Picture object black?

Karl Ottenstein — Sun, 23 Dec 2007 20:03:20 GMT

Palawat wrote:
If you start with internal engine, don't forget to click the "Match Internal" box in lightwork engine.

or maybe you can show us the screen shot of how you set your material.

One does not define a material for use with the TV object - so this is not relevant.

Karl

Re: Picture object black?

Karl Ottenstein — Sun, 23 Dec 2007 20:08:19 GMT

Grant wrote:
Does anyone know why my custom picture shows black when I render? It shows up fine in the 3d window but when I render it the custom picture turns completly black.

Im using v11 and rendering in lightworks. Sun and sky objects and window lights.

You didn't say which TV object. The attached shows 'PlasmaTV 11' with a jpg image captured from CNN (copyright them, yada yada).

The TV does not illuminate itself, nor is it defined with a LW constant shader/etc. So...you have to shine a light on it to see the image. In the image below, I turned on the camera light (LW rendering dialog) just to be quick about it to make sure the object works the same as it always did.

Your image file MUST be in a loaded library. Enter the file name, not the full path. You'll get an error in any case if you enter the name incorrectly.

Also - there is a bug that has been in this object for years: the image you give it must be the mirror of the one you want to see. (If I look at the jpg for the CNN image shown below, the text is backwards - I had mirrored in in Photoshop to get it to show up correctly years ago.)

Cheers,
Karl

Re: Picture object black?

Dwight — Mon, 24 Dec 2007 00:54:06 GMT

Solving a glowing surface like the plasma screen is a multi-stage process, the least of which is the black screen issue.

Yes, the image must be loaded with the library for the data to be employed, but this method produces a flat and uninteresting screen that emits no energy. In all but the brightest situations, it looks artificial.

As Karl alludes, there is a superior solution that can employed for any glowing surface like a backlit advertising sign or aquarium. This solution is featured in my book - page 138.

In that article, I place a thin wall directly in front of the plasma screen, using a wall material with a Reflectance Shader "Constant." The television image is exactly the size of the inserted wall. It is aligned to fit with the 3D Align Tool.

The picture image used as the wall material should look slightly overexposed - you do this in photoshop.

To project diffuse glowing energy into the room requires a wide light cone placed directly in front of the screen.

Re: Picture object black?

Dwight — Mon, 24 Dec 2007 00:58:58 GMT

and the effect

Re: Picture object black?

Karl Ottenstein — Mon, 24 Dec 2007 03:45:31 GMT

Beautiful, Dwight!

Cheers,
Karl

Re: Picture object black?

Palawat — Mon, 24 Dec 2007 18:35:00 GMT

WOW, Dwight.