projector

[Makushimu]

How to make a projector out of light, projecting an image onto a wall?
In vray 3.7 I used a plane with texture and in the transparency channel I let a light source pass through it.
In 5, it doesn't work or am I doing something wrong?

[shaio]

Hey Makushimu ,

You should make the light directional for this to work. The lights in V-Ray 5 are now separate objects and not tags so difference in the workflow is expected. Take a look at the screenshot and play around with the directionality of the light until you have the desired effect.

[Makushimu]

Thank you shaio
But I can't make it work.
What are your other light settings?
Where to put the texture?
How to make the projected image / texture rectangular?
Can you upload a sample scene?

[shaio]

Sorry, I saw that I didn't select the texture tab, so you can see how it is applied. You need to put the texture in the slot inside the texture tab. I'll upload the scene for you.

[shaio]

i've created a new scene for you since I didn't save the example I shared above. Feel free to replace the currently assigned texture to the light with whatever you see fit. The only thing I changed for the light is the intensity, size and the directionally.

[Makushimu]

Thank you.
I built it the same way, but it doesn't work for me when I build from scratch.
In the new scene, when I set the light like you did, texture it, nothing renders.
When I open your scene I just change the texture to mine, the texture is projected and rendered. The only problem is that it's very blurry. How to make it not so blurry?

[Makushimu]

Ok, when I set the directional to 1, there is no blur.
But why does it only work in the scene you have prepared?

[Makushimu]

I have another problem.
I have to project the image onto the floor from a height of about 3m (the light source is small as in a real projector). The projected image on the floor should be in a rectangle of about 2x3.5m and it should not be blurry.
Any ideas?

[Makushimu]

For now, the only sensible solution I have found in this case is to use two separate lights. One pretending to be light coming from the projector lens, the other pretending the projected image on the floor.
It would be nice if you could get a similar projection effect with just one light, as it was in version 3.7.

[YunalZobu]

Do you mean something similar to this?

[Makushimu]

Do you mean something similar to this?

As you show it is possible, obvious. But then the light have to have the same size as the projected image, and vice versa.
My point is that the light could have a size, for example 2x2cm, and project a not blurry image, for example 300x300cm.
Now if you want to display the image bigger than the light you need to reduce the drectional. As you reduce the directional, the projected image becomes blurred.

I would like to be able to have small size light projecting big image with no blur.

[YunalZobu]

I'd approach it a bit differently.

I'd just use an Area/Rect Light for the actual illumination (so the visible image being cast from the projector) and for the "source" of the light (so the lens or the object behind it) use a Light material.
That way you can have greater control of the light in LightMix and still have the Lens effects being applied on the source.
Hope this helps

[Makushimu]

I'd approach it a bit differently.

I'd just use an Area/Rect Light for the actual illumination (so the visible image being cast from the projector) and for the "source" of the light (so the lens or the object behind it) use a Light material.
That way you can have greater control of the light in LightMix and still have the Lens effects being applied on the source.
Hope this helps

In the end, I also did the same. But instead of light material, I gave the source second ordinary light.
However, I think it would be more logical and simpler if it could be controlled from a single source light. Just like the real thing. Otherwise it's like cheating.

Thank You.

[RwVision]

In the end, I also did the same. But instead of light material, I gave the source second ordinary light.
However, I think it would be more logical and simpler if it could be controlled from a single source light. Just like the real thing. Otherwise it's like cheating.

Thank You.

Agree here 100% I did a scene with a projector some time ago in 3.7. Small light source, projecting bigger image just like in real life.
https://www.dropbox.com/s/4ygxz70pii...ector.mp4?dl=0

And there's more to it - creating an animation like this, you would not fit the big fake area light into the room and avoid light artifacts.



shaio
Why in Vray 5 it is not possible? Seems like a big step backwards.

[Makushimu]

Why in Vray 5 it is not possible? Seems like a big step backwards.

I cannot disagree.

I hope this functionality will come back as soon as possible.