Shadowless prims?

[Finite]

I am trying to make a prim not cast a shadow. Someone referred me to PRIM_CAST_SHADOWS but I have been struggling to get it to actually function.

[Finite]

Actually just figured it out. Doesn't require a script at all. 

[KT Kingsley]

Yeah, according to the wiki PRIM_CAST_SHADOWS is so deprecated it doesn't work at all any more, since version 1.

Please tell how you got your effect. It's not something I've ever needed, but I couldn't come up with any ideas, and it's always good to learn a new trick.

[Finite]

It's done by simply selecting alpha masking under "alpha mode" after you have applied a texture.

[Qie Niangao]

If the masking cutoff threshold is set to make the object fully transparent, then yeah: no shadows. But that's kinda the long way 'round the barn. Masked alpha surfaces do cast shadows from the opaque parts - they can even be animated to create moving shadows - so I'm curious what's really going on here.

[Kyrah Abattoir]

Same...

[Finite]

Not sure but I had an issue and doing that resolved it. Changing the masking doesn't make the object transparent. It only makes it act as if it is. Basically I wanted to put up a big giant green object in the background for taking a photo without it interacting with the shadows and light. Basically I did not want this object to cast a shadow and basically act as if it wasn't there.

Edited September 4, 2020 by Finite

[KT Kingsley]

1 hour ago, Finite said:

Basically I wanted to put up a big giant green object in the background for taking a photo without it interacting with the shadows and light.

Set it to fullbright.

That sounds like what you actually wanted was a green screen background that didn't have shadows or other lighting effects cast upon it, rather than an object that didn't cast shadows.

Edited September 4, 2020 by KT Kingsley

[Finite]

 

3 minutes ago, KT Kingsley said:

Set it to fullbright.

Yes I did that but that in itself doesn't make it not cast as shadow lol.

[Qie Niangao]

My confusion is that I'm unable to replicate the effect of stopping shadows from surfaces set to alpha-masking.

As far as I know, it's only even possible to set this on surfaces that are currently using a (32-bit) diffusemap texture with an alpha channel, so if it's 24-bit opaque, that won't work. But when I've tried it with an alpha channel texture, setting it alpha-masking still casts shadows from any part of the texture that isn't transparent. In fact, with an alpha gradient texture, I can adjust the masking threshold with the effect of changing the area that casts shadows. So it seems as if something else is happening, I just don't know what. If a particular texture works this way, it would be great to know what makes that texture special.

[Wulfie Reanimator]

1 hour ago, Qie Niangao said:

My confusion is that I'm unable to replicate the effect of stopping shadows from surfaces set to alpha-masking.

Because as I know you know, that's not what alpha masking does.

 

Edited September 4, 2020 by Wulfie Reanimator

[Mollymews]

On 9/3/2020 at 1:56 AM, Finite said:

It's done by simply selecting alpha masking under "alpha mode" after you have applied a texture.

Finite, you are correct about not having to use script. Alpha mode is not necessary tho, but you have the right idea that it is transparency solution

set the sun side of a prim to 100% transparent, set the green/camera side to opaque