[Tim Ellis]

Tim nice work? are you planning to share your glass material on the MXM library?

that would be very cool tim.

It's a wizard high grade glass with 255 green tint. So no need really

Then for the object you want to be glass, which shows shadows, turn on 'Hidden to GI' in the object parameters dialogue.

wonder.. this "new type of glass hidden to GI " gives correct refraction? it seems to me it doesnt .. if this is true ( but i could be wrong) it doesnt solve the major problem with AGS : the fact that it doesnt have refraction....
in case refraction works ( in effect they should) why not use a glass hidden to GI but visible to the camera in conjunction with a glass visible to GI but hidden to the camera ? thats also for water... perhaps it gives the right risult.( we could eventually obtain water with caustic and correct refraction at the same time, which could not be obtained with ags + hidden to camera water) .. must try.. or have u already tried Tim

Refraction looks accurate, but no caustics are shown in areas viewed through 'Hidden to GI' glass.

Will test more with different combinations of hidden parameters.

I'm currently running a 'Hidden to camera' test, which also has a 50% high grade green glass, with 50% AGS material.

Great work Tim,

i want just ask again someone from NL or A-team. Is it bug if i place glass in front of camera and every objects not visible to camera became visible through this glass?

Patrik

Noticed some strage refraction going on in my latest test too. Will post results later.

Tim.

[giacob]

so even if hidden to GI is activated standard glass can avoid hiding caustics seen trhough it ... too bad ... it neans that we cant have a pooll with caustics and correct refraction...

[Tim Ellis]

Giacob, check these latest tests. I have some refraction with mxms & shadows. Will test your pool problem though. Not thought about that application yet though.

Scene layout. Hidden wireframe view:-

Render:-

Overlay:-



50% AGS & Glass MXM is a High grade glass preset, coloured slightly green in transparency. This is set to 50%, with an embeded AGS_Dielectric_Basic mxm, which has adjusted bsdf layers set to 42.5% & 7.5%.

Glass object in front of camera, is to simulate exterior to interior camera view. It's a 30' smoothed cube 20mm thick, with 'hidden to GI' enabled and a high grade glass mxm. The edge of this 'window' can be seen in the bottom right of the image.

Ammended:- Regarding the shadow that crosses the center of the image, which I've highlighted in the overlay image.
I couldn't identify this earlier, but now have in my later tests. The line is the floor cube refracted due to the 50% AGS & Glass mxm.

Right hand glass object, is cloned and scaled, 1.001 xyz, to produce the outer 'jacket'.
Inner object is hidden to GI but visible to camera and outer object is visible to GI but hidden from camera.

Need to do more tests with hidden to parameters.

Conclusions:-


50% AGS and glass mxm gives correct shadows, including correct darkness of shadow, for a 'hidden to GI' object.
This is true for sunlight passing through glass, which is viewed through glass, from the exterior of a scene into the interior.

Due to the 50% mix, there is some refraction present, but currently no caustics.

Having a combination of 'Hidden to GI' and Hidden to camera, doesn't seem to improve things.

More tests with spheres to check refraction levels.

Tim.

[Tim Ellis]

Result:- Sorry for my terrible spelling in the images.


Showing that you don't need 'Hidden to GI' enabled for an object when using 50% AGS & Glass mxm.
Although you do need to have exterior windows set to 'Hidden fromo GI' enabled.
However if just Glass mxm is used, then 'Hidden to GI' needs to be used for that object and an AGS 'jacket' object for object's own shadows to be seen.



Refraction and correct shadows, using 50% AGS & Glass mxm, no 'Hidden to GI' for sphere objects. Glass mxm 'window' object is 'Hidden to GI'.


Final note on refractions in the camera 'window' object.
These are produced by using the 50% AGS & Glass mxm.

50% AGS & Glass MXM will be in the mxm gallery soon.


Last test cooking now with griduv.jpg applied to the floor object, to show refraction and hopefully show some caustics. Not left these renders cooking long enough for them to show properly.

Tim.

[giacob]

TIM....we all are gratefull to u about those scrupoulus and interesting tests

[Tim Ellis]

No worries mate. I really enjoy the research and development side of using Maxwell.


Tim.

[numerobis]

Thank you very much Tim for all this testing! VERY helpful!

and thanks for uploading the material!
i'll test it as soon as it's in the gallery

[Tim Ellis]

You're welcome.

MXM named:- Sun Shadows through glass

Should be available soon as I've uploaded it.


Tim.

[Maximus3D]

Good work Tim and nice to see such creative use of the materialeditor this must have required some serious brainstorming to figure out.

/ Max

[Tim Ellis]

Cheers Max.



Refraction, of sorts, with correct shadows. Shadows are not as easy to see with this colour map, compared to the 80% roughness shader.

Same Glass mxm ''hidden to GI' camera 'window'. Spheres are 50% AGS & Glass mxm, visible to GI.

Tim.

[def4d]

awesome research!

Are caustics possible? i can't see them in the renders

[mashium123]

Great effort Tim. Thx a lot for your work.

One question though... could you show a 'real' render where you'd use this mxm? Like a window shot in an arch-viz or such?

It's just... I have difficulties to recognize this mxm as something glass-ish... for me it looks more like something plastic-ish or like a bubble (i.e. the standard material scene render) or such...

Maybe it would help to see the mxm in a 'typical' glass scene, just to see if this mxm would really 'work'...?

[leoA4D]

Tim, this is really instructive. Well done and thanks. I agree with mashium's suggestion and would like to see a graphic explanation, like yours above, next to the rendered example.

Please do and share more of your MWR experiments. Good job.

[Tim Ellis]

I will do, I still need to clarify the last few aspects involved, after running some more tests.


Quick example:-

Exterior camera shot of an office tower lobby interior. Sunlight positioned so sunlight fills the lobby.
Use glass mxm on windows, one solid shadow produced.
Use 'Hidden to GI' for windows, window frame work shadows produced, sunlight where glass. No refraction or caustics - same as using AGS mxm.

Apply 50% AGS & Glass mxm, visible to GI, to windows and limited refraction with correct sunlight shadows.
Camera, however, needs to look through 'Hidden to GI' glass mxm window. I need to clarify this!!

Tim.

[KRZ]

i need to clearify this

and NL should try to implement that hack if it turns out useful.