Zomg I searched the forum and found no topics talking about how to make glass allow light to pass through

I turned Ztransp on… I tuned down Alpha Turned Fresnel up… Turned IDR up… to 1.5… Lowered Spec Tra and rendered and tried it w/o all these things… in certain combinations…
I even turned TraShadow on… I am using a Spotlight. Tried it w/ shadowbuf off…

ZOMG… it just fails to work,… i am trying to get light to pass through this friggin wall like in this:


Ensure you’ve enabled raytracing (select Ray in the render options - looks like you have probably already done this) and make sure you’ve enabled TraShadow in the material of the object receiving the shadow (i.e. the ground plane).

Make sure the light your using has ray turned on.

well i did it but now my image still casts a shadow but now its just a bit more transparent. I want the object to actually let Light go through it like a window (trashdo was off lolz thats why i didnt get this far b4 lolz , i put it on the trans object but not the surface.)

I want to achieve something more like this:

(both images from lighting challenges on CGsociety)

So i want the object to cast light… not shadows…
Is that radiosity?

Looks to me like RayTransp isn’t turned on.
It’s just above the IOR button (index of refraction)

If you start with a default scene, add a plane under the cube then

(a) turn the cube’s material alpha down to 0.1
(b) enable Ray Trans
© set IOR to 1.15
(d) create a material for the plane and enable TraSha

then render, you’ll get this: (don’t worry about the bottom of the cube - it’s sharing space with the plane, if the cube were raised a teensy bit of the plane, the prob would be gone)


Ya i got that but I am wondering… How do i get Light to pass through the object and cast light on the other side instead of the shaddow… an object w/ NO shadow but also that allos for “translucecy” (Allowing the light to pass throught but therefore altering the light, ex: red glass… white light, Light hits glass comes out on other side as red.


Your setup is the complete opposite of the image of the window you’ve included! The glass isn’t casting light - it’s actually blocking a small amount of light. However, the walls are blocking all the light, so the window seems to be casting light relative to the walls.

If you want to replicate something like that, you just need an opaque wall with a hole cut out of it to let the light through. You can put your glass into that hole (enabling raytracing wherever required) and set TraShadow on the floor.

hmmmm… I will try it and see.
I hope i get it to look like this… and not keep casting shadows onto the floor.

I have had raytracing enabled and raytransp on and everything… but it just made the shadow lighter. hmmm

JEJE i figured OUT WHY IT wasnt rendering how i wanted to… If i tried the same setup but w/ an elevated surface w/ a light coming through i would have got the correct results thnx dude:

Alright, you win!! Here you are, look at this blend file.

I’m not sure from your posts, do you realize that there’s almost certainly more than 1 light in the image you present? Another thing to notice, is that the window’s light is bound to have the Energy cranked up a fair bit, so as to produce the nice light spot on the floor. You could always go for a more physically accurate model of the light, And (I suppose?) turn on raytracing and large numbers of RayBounce, before rendering with YafRay or even Indigo.

I am also not at all sure that Blender can do the volumetric fog like that yet, I think (s)he’s faked the effect of the light passing through something that’s in the air.
This will present another challenge to you, there’s bound to be info around on how to do it.


A shadow-buffered spotlight with Halo steps greater than 0 should do the trick nicely.

Well ya but buffered lights dont pass through transperant objects. =(
Thats a problem i am getting lolz Buffered lights wont pass through objects but i want a volumetric shadow to appear.

Another question; what renderer is best for more “Realistic” results… I so far know that yafray pwns internal… but what else are there… so far i have only heard of Yafray, Indigo, and lately Maxwell.