Lampshade transparency

[Tic]

Hi everybody,
I’m an enthusiastic recent SH3D user.
First of all let me congratulate the developers team on sharing this excellent tool. [=D>]

I’m practicing with models and light and I’m trying to obtain a realistic rendering of a translucent lampshade.
I made some tests modifying Ni parameter in .mtl file, but I had no satisfying result.
Here an example of the effect I’d like to obtain.

Can anyone give suggestions?

Thanks

[Puybaret]

From the MTL specifications, the Ni value is for optical density or index of refraction and not transparency.
You should better play with the d value which is the transparency factor from 0 (fully transparent) to 1 (fully opaque and default value).

I'll be happy to see the results of your tests. [:)]

[Tic]

Emmanuel, thank you for your prompt reply!
Ok, I tried with d = 0.32 on a 20x20cm empty box (with 1mm thick walls) that I put in upside-down position on the floor of a dark room.

Inside the box I put a 10x10cm light source hanging at 10cm elevation.

Unfortuntely the resulting Q4 photo is still far from my targert: there are black shimmers on the box surfaces and some light escapes from the bottom of the box [:(]

I would have sent you an image, but sorry, I just cannot find the proper "attach file" or "upload image" option....

[Puybaret]

Here's an example I built from partially transparent round walls exported then reimported. I put this shade on on a small floor uplight to make it look like a small lamp.

[Tic]

Wow, that's quite similar to what I mean... I'll let you know my further steps..
In the meantime you can have a look at my poor result...


Thank you!

[Puybaret]

Be sure to give the lampshade a color darker than white otherwise it will be rendered completely transparent. You can test also with textures but it might be buggy like here.

[Tic]

Emmanuel, could you please post the mtl assignments of your cylindrical lampshade? I'd like to compare it to mine.

[Puybaret]

Tic if you want to know these values, just create an empty document in which you copy/paste only the lampshade and then export it to OBJ format.

[Tic]

Great!
Thank you so much.. sorry..I'm sitll learning.. [:)]

[Tic]

Emmanuel,
I'm back after more tests: I think that the bad rendering is due to the Obj export method of the modelling software I use (Wings3D).

On the left you can see your original lampshade and on the right the same object imported in wings3d and then re-exported as .obj.
I manteined the same mtl file for both.