View Full Version : How to get only reflections?

08 August 2003, 09:20 PM
I have been strugling with this for a while, managed to get decent result with lightning so that everything else was pure white, except object and reflection. Anyway, I was wondering if there's some easier way to achieve this???

08 August 2003, 10:15 PM
i think i know what you mean, can you explain a little more.

for your lights properties you can uncheck diffuse, and leave spec.
i think that might work, if i know what you're saying

08 August 2003, 08:23 AM
Well, actually no. Sorry for bad explanation :). Let's say that I have this box and reflecting floor. And I want to .. umm.. get only that object and it's reflection. Object is easy to get with alpha-layer, but how do I get that reflection also?

08 August 2003, 08:34 AM
not sure about the reflection, I know you can get the shadow.

good question, you may have to fake it, flip it backwards/upsidedown, fade it onto the surface you want.

anyone else???


08 August 2003, 10:00 AM
generate a quick alpha for object and it's reflection by setting the object''s Matte setting. I made a cube and set it's matte color to white. Everything else was black and the object and it's reflection were the only things visible. Once you have this mask/ can use it to isolate the elements in your standard render.

You could probably achieve the same rendering results with a white, 100% luminous preset, but matte is quicker and easier.

hope this does the trick for you.

08 August 2003, 10:39 AM
Use Photoshop export ...

08 August 2003, 02:19 PM
I would do just like Eugeny suggested. Go to Image Processing (under the scenes tab), click 'Add Image Filter' scroll down and select Photoshop PSD Export. Then double click on it and then you can select anything you want to render and export out to a seperate file. Then all you have to do is go into Photoshop, DFX, Combustion, AE and recomposite the images together. Be warned AE does NOT allow direct/correct importing of psd layers! There are work arounds just do a quick search on PSD layers and you will get the answers on how to do it.

08 August 2003, 04:18 PM
Here's what I got, using what I described above.

The image:

The mask:

And the final product:

You only see the object and it's reflection, nothing else. :)

08 August 2003, 06:27 PM

excellent example!! it would be nice to see more ppl take the care to show what they say!

well done

08 August 2003, 03:08 AM
thanks dude. The urge to communicate wrestles with the urge to not care..but usually when i post, it's because the first urge won out.

08 August 2003, 04:30 AM
Hmm im a lw noob, so i didnt completely understand what you did. Can you please explain in a lil more detail?

08 August 2003, 05:36 PM
Step 1: Render your scene normally, saving out either an image sequence or some sort of movie file.

Step 2: Select the object you want to isolate. Bring up it's object properties and go to the Render tab. Check "Matte Object" and set the Matte color to pure white.

Step 3: Go into the surface editor and modify all the surfaces that don't belong to your single object. Set the the diffuse and specularity to 0%. If there is any reflection value, change it to 100%.

The scene should now be set to render a sort mask of the single object and it's reflections.

Step 4: Render the modified scene, saving an image sequence or movie (with a name that includes "mask" to make your life easier)

now, for the compositing in Lightwave (if you have other software, you can use that instead)

Step 5. Make a new scene.

Step 6. Bring up the Image editor. Load both the original animation and the masked version.

Step 7. Bring up the Compositing effects window (under the scene tab or press CTRL-F7)

Step 8. Set the foreground image to the original animation. Set the Foreground Alpha to the masked version. Make sure to check Foreground Fader Alpha. Foreground dissolve should be left at the default of 0%.

Step 9. Render out the new animation. This should be just the object and it's reflections, since the rest of the objects in the original animation will be masked out.

there ya go. Let me know if there needs to be any clarifications or changes. Step 6 could certainly be bypassed by choosing "load image" in the Compositing drop downs. I only used it to keep a sort of logical flow in the steps. :)

08 August 2003, 05:28 AM
thank you very much

08 August 2003, 08:29 AM
Thanks zuzzabuzz, that's a nice way to achieve this. And thanks to Eugeny also, nice to know that photoshop export.

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