How to make a wall that acts like the ground plane?

Started by Esben Oxholm, December 20, 2012, 11:46:15 PM

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Esben Oxholm

Hi!  :)

Is it possible to make a "wall" that acts like the ground plane? Recieving shadows and being invisible.

A have a wall hanged box, that needs to cast shadows down a wall and not only on the ground.

Is this possible? A material, render pass, other? Anything will do :)

Thanks.

PhilippeV8

I keep running into the same issue.  Thus far, my best sollution is to position your object flat on the ground, then position the camera such that it looks like hanging from a wall.  It's a bit tricky, but it works.

Esben Oxholm

Too bad... can't really get the angle right this way. I'll have to fake the shadow in PS then.
Thanks for the reply :)

guest84672

Can't you import a plane, and texture it to make it look like a wall?

Esben Oxholm

Not really.
I want to use a backplate image as wall. An office environment with a lot of detail in the background. Like all the car renderings on backplates... just with the shadow on a vertical plane instead of the horizontal ground plane.

Maybe it is possible to create a 100% transparent material that only recieves shadows. No highlight or reflections at all?

guest84672

I think this may be possible with render layers in KeyShot 4.

DriesV

Quote from: Thomas Teger on January 03, 2013, 07:24:08 AM
I think this may be possible with render layers in KeyShot 4.

Aha, so KS4 will allow to put shadows on a separate layer?

Dries

br3ttman

Can you give us an ETA on KeyShot 4.0?  I'm still waiting on something from Santa  ;)

guest84672

Shadows on separate layers - not yet. KeyShot 4 - early this year.

Speedster

How about putting your backplate as a label on a large vertical plane?  You would get shadows, but of course they would not travel over objects in the backplate.
Bill G

Airwaveflyer

Ok, here's a way to do it the quick way...

Tilt the backdrop 90deg in PS so that the floor you want to mount it on is down. (of course :-) )
Bring up the resize image window in ps...type in 800-1000px in the field with the highest number (w or h). note the to values on a piece of paper. (800x?? or ??x800)
Also take a note on the full resolution of your backplate. Press cancel. (you don't want to resize it, just get the values with the same aspect-ratio as the full image.)
Save the image on the desktop

Open up Keyshot...set the windowresolution to the noted values.

Drag and drop the backplate onto the background.

Now import your model and place it on the wall (floor) where you want it.
Setup materials and light it.
(if you are using a matching HDR to light the scene,..you need to rotate it in for example a plug-in called flexify before you can use it.)

Activate global illumination and ground illumination.

Render as Tiff or PNG in the full resolution of the backplate.

Open up in PS and rotate it to correct orientation..

Open up Original backplate and Shift-drag the rendered image onto the backplate

Do final adjustments in PS and finished!

Hope you find it useful

(Lampmodel from Grabcad and backplate from FLICKR.COM/74783045@N00)

KeyShot

KS4 will have a new ground material that will make this easy to accomplish.

Esben Oxholm

Thanks for the detailed description Airwaveflyer.

Sounds great that it will be possible with KS4.
Can't wait to check it out :)

PhilippeV8

Quote from: KeyShot on January 09, 2013, 12:52:18 PM
KS4 will have a new ground material that will make this easy to accomplish.

Does this sound like you can aply a "ground" material to an object, then have a TIFF render with the shadows that fall on any object with this material included in the alpha chanel, while other parts of that object that have no shadow are left out ?
If so, I can't tell you how many reasons I have come across thus far why I need KS4 like ... yesterday  :D
(Also the PNG making with transparency instead of a TIFF with an alpha chanel ..)

I am working on a set of PNG files at the moment which holds one of our terrace covering products in layers for an iPad app where the user can put a picture of his home in the background and then puzzle our product on top and change color etc etc.
So I am making hundreds of PNGs with various bits and colors and shadows ...