Reflection

Features you'd like to see in future versions, gripes, ideas..
marchab
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Reflection

Post by marchab » Fri Jun 27, 2008 1:39 pm

LU is just great as it is already!
Just want to know, would a certain amount of light reflection be possible? Like on glass panes?
Full reflection?, like mirror or chrome?
The ease of use of LightUp is a tremendous asset!
Mario C, SketchUp & LightUp trainer, Mac & pc

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AdamB
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Re: Reflection

Post by AdamB » Sat Jun 28, 2008 11:27 am

marchab wrote:LU is just great as it is already!
Just want to know, would a certain amount of light reflection be possible? Like on glass panes?
Full reflection?, like mirror or chrome?
The ease of use of LightUp is a tremendous asset!
LightUp has always supported reflections!

Simplest way is add a skybox to your scene. Create a material with a loaded texture from disk that also has a normalmap.

For example if your texture is called "mytexture.png" there must be another texture in the same directory called "mytexture_uvlmap.png". LightUp will pick up this normalmap automatically and create a material with specular reflections.

Here's an example I use for doing windows. You'll need to set the Sketchup Material opacity to around 25%
glass.png
glass.png (155 Bytes) Viewed 11305 times
glass_uvlmap.png
glass_uvlmap.png (155 Bytes) Viewed 11305 times
Adam

UPDATE: Correct info, just I think I've screwed up those textures. I'll post some better ones later.
Developer of LightUp http://www.light-up.co.uk

gaganraj
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Re: Reflection

Post by gaganraj » Mon Jun 30, 2008 2:06 am

is there anyway to do a reflection tutorial? thanks! great plugin btw!!!! :D

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AdamB
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Re: Reflection

Post by AdamB » Mon Jun 30, 2008 11:35 am

gaganraj wrote:is there anyway to do a reflection tutorial? thanks! great plugin btw!!!! :D
Yes, planning on providing one soon.
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marchab
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Re: Reflection

Post by marchab » Mon Jun 30, 2008 2:27 pm

AdamB wrote:Yes, planning on providing one soon.
Good ! I do think it is greatly needed. 8-)
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marchab
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Re: Reflection

Post by marchab » Tue Jul 01, 2008 2:06 pm

AdamB wrote:UPDATE: ... I think I've screwed up those textures. I'll post some better ones later.
Hah... May I kindly ask if you could please provide those "better ones" as soon as possible. I would very much like to test that feature while I have time for LU.
I do not want to trouble your priorities thought.
Mario C, SketchUp & LightUp trainer, Mac & pc

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AdamB
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Re: Reflection

Post by AdamB » Wed Jul 02, 2008 12:13 pm

marchab wrote:
AdamB wrote:UPDATE: ... I think I've screwed up those textures. I'll post some better ones later.
Hah... May I kindly ask if you could please provide those "better ones" as soon as possible. I would very much like to test that feature while I have time for LU.
I do not want to trouble your priorities thought.
Its pretty easy to generate _specmaps for LightUp. Just get a texture you want to use into a PaintShop Pro / Gimp/ PS etc and generate a grayscale version, save it as originaltexturename_specmap in the same folder as the original and you're done.

LightUp picks up the specularmap, automatically generates a normalmap from your original texture, folds in your specularmap and continues on.

Adam
Developer of LightUp http://www.light-up.co.uk

marchab
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Re: Reflection

Post by marchab » Wed Jul 02, 2008 3:48 pm

I agree, that it seems easy. So ulvmap in the previous post was a mistake I guess.
One more precision, please.
For glass, transparency is set by the SU setting, right ?
How do can one control the level of reflection? Like brushed aluminium vs chrome, for instance.
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AdamB
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Re: Reflection

Post by AdamB » Wed Jul 02, 2008 5:13 pm

marchab wrote:For glass, transparency is set by the SU setting, right ?
Yes. It also multiplies in the alpha in textures, so you can get some nice effects with textures that have alpha. Try the SU material "Fencing_Diamond_Mesh":
SketchUpScreenSnapz021.png
SketchUpScreenSnapz021.png (78.94 KiB) Viewed 11124 times
marchab wrote:How do can one control the level of reflection? Like brushed aluminium vs chrome, for instance.
That is what the specmap does. For each texel it says how reflective it is: white means full reflective, black means none.

Internally, LightUp uses a single map that contains a normalmap, specularmap and Fresnel term all packed into RGBA and this is what a _uvlmap actually is. The channels Red & Green are the normalmap, Blue is the level of reflection and Alpha is Fresnel term. So when you give LightUp a _specmap, it actually builds the uvlmap automatically but replaces level of reflection with that taken from the specmap.

This ordering of components is cunningly chosen so you can actually just take a regular normalmap and give it to LightUp as a _uvlmap and get a reasonable result.

Enjoy,
Adam
Developer of LightUp http://www.light-up.co.uk

marchab
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Re: Reflection

Post by marchab » Wed Jul 02, 2008 6:18 pm

Oh, I must say I'm a bit confused now as to how to name the material files.
Do we need 2 or 3 files; mytextur.jpg, mytextur_ulvmap.jpg, mytextur_specmap.jpg?
Anyway, I think I finally succeeded in getting some reflections (using mytextur.png & mytextur_specmap.png (the latter for greyscale)).
I am surprised to see that the skybox reflects alright but not the objects of the model.
The glass on top of the base box, which is the same as the one on the front side, does not reflect the stone podium on it.
I must be missing something, no?
refl-1.png
refl-1.png (195.57 KiB) Viewed 11115 times
And this not quite it, yet. The walls are transparent to the skybox reflection!
Attachments
refl-2.png
refl-2.png (133.32 KiB) Viewed 11089 times
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