Cineversity

Hello

This is another more generic question.  I often receive geometry that comes from CAD software, with un-optimized topology, and I have to video projection studies on it.
One thing that has been seeming like a waste of time is combining all the geomtry together and then creating individual textures per video projector to isolate camera projection textures.
Is there an easier way to approach this?  Basically the perfect setup would be to approach this as gobo’s work in C4d, but for video

Does that make sense?

Thanks!

Hi Alex,

This would be normally answered with: A light can hold a texture. However, I found it always a little bit less intuitive to do so.

Please have a look at the project file below:
https://www.amazon.com/clouddrive/share/JwQIRZs3b2fEzI4rCwIL0idjvdPn9gL5S8LuaZ72GrY

This is closer to the Leko (Lekolite) that is used with a Gobo “on set” (or more often in theatre).

If that works for you, I could set up a little expresso that allows adjusting the Light source in Beam-Angle for H and V as well based on Ratio (as in 16:9), to make it usable for any formats used these days. Just let me know.

Cheers

Oh nice!  This is amazing, yes a setup that allows me to make it behave more like a projector would be really really useful! 

Thank you!

Alex,

Please have a look here:
https://www.amazon.com/clouddrive/share/NtgmYvSYEohgSkqFetiHxirwaJKh3p4Dytw11Lma6ID

I have included a little screen capture, as well.

(Not crucial but to be complete: The light source has a counter-intuitive aspect ratio, hence my 90º and -90º in the Coord/Freeze section.)

Let me know if that works for you.

Cheers

This is truly unbelievable!  I’ve been looking for something like this in C4d forever!  Recently I had to start using this online tool called MappingMatter.com to achieve this kind of result. 
I’m so grateful for this!!!!
Thank you!!

Thanks a lot, Alex, for the kind feedback.

It makes me happy to read that this works for you.

As usual, my best wishes for your projects!

Cheers

Hello Sassi! 
I’m coming back to this thread because I’m needing to do a quick projection study, and have been looking through some of our old conversations.  I’m trying to find a way to replicate, in C4d, certain pieces of data about a real world projector.  In particular I’m dealing with this projector : https://epson.com/For-Home/Projectors/Home-Cinema/Home-Cinema-1060-1080p-3LCD-Projector/p/V11H849020
Obviously the focal length etc is a hard to translate in the setup you have here with the light. 
What I’m trying to do is to show a museum person where people will cast shadows if this projector is hitting a wall…

Let me know if you have any thoughts on how to translate this to your lighting system above?

Thanks!

Hi Alex,

The only data they have
Focal Length:
18.2 mm – 29.2 mm
The 300” diagonal isn’t very precise without providing any information at what distance it will be.
But sadly, not anything how large the “projector-light” element is that emits the light. It is like that nonsense when people say that lens has a crop-factor. Lenses do not determine that. The larger the element is, the larger the field of view.

Do you have any field of View data?
I could set up something, but so far, I miss data.

All the best

P.S.: I found something. I will have a look after lunch into it
https://www.projectorcentral.com/Epson-Home_Cinema_1060-projection-calculator-pro.htm

Hey Sassi!

I have this : 10.2-1.23 f.23 f/1.6-1.7.
Does that help?

Thanks!

Hi Alex,

I got all information from the link I have found (Post 7 P.S.)

According to this, the 16:9 is the native size of the element, and with 4:3 is pillow-boxed (smaller in width). I go with the 16:9 as I do not really believe it would make any sense to lose a quarter of the resolution.

I assume the “10.2-1.23 f.23 f/1.6-1.7.” is the precise zoom Facto and the resulting F/value - which is not saying anything about the “field of view”.

Please explore the file below: [01]
https://www.amazon.com/clouddrive/share/1qAU2B3uROZ0s27sReKv32YCyzUmIZduzXmiknxossV

You can replace the grid with any footage you have.

Move the light and leave the child of the light as it is. The Zoom Slider is a User Data of the Xpresso Tag.

I have two screenshots from the calculator included, and the two planes in the scene mark the 1.0 and 1.2 settings.

I did not include the v/h shift options; let me know if that is needed.

All the best

Hey Sassi!  This is great!
I can totally use this.  Would it be hard to add lens shift?  I could certainly use it!

Thanks SOOO much!

You’re very welcome, Alex.

I’m not certain how Epson does the shift. Most of the time, I saw that the image just moved. I think the adjustment while the image center stays is not that often in consumer projectors, like the one I have.

Please look at the little square HUD. You can move the projection with the mouse indicator. However, I was not clear if the total shift was 30º or to each side vertically/horizontally.
[11]
https://www.amazon.com/clouddrive/share/Q4iR9d2UWBT26P6tLQIEvqQ4fomuxWG73hkLWTyqc2f

All the best

P.S.: …perhaps the Cube “projector” needs a Compositing tag set to Not Seen By Camera.

P.S.:
Here is a version [21] with shift option while the Image stays more in place.

All three versions are in the link
https://www.amazon.com/clouddrive/share/qBwKr1gLLFGIjqoYIdLXVUD3pQ2l13cjEeOSKihKjRE

Hey Sassi!
Thanks, this is great!
I think it would be super valuable to somehow transform all this work you did in a general purpose “projector” tool that would allow people to enter user data that takes typical projector information (lens/fov/throw/resolution) and gives you an equivalent “light”/projetor setup.  It feels like a needed tool for so many C4d users…For example if I wanted to use a different lens, what values would you change in your Xpresso setup?

Thanks so much for this, really amazing to have, now I can present the projector position I need very accurately.

Thanks for the feedback, Alex.
Yes that would be great, if all data would be available for an easy use.

I have placed the values I got from the Epson site as accurately as possible, and so far, I can tell they match. But please check with the projector if these numbers match. The remote control has different vertical adjustments than the Specification tells.  Please check them with the projector. There are conflicting numbers with the shift angles.

With a zoom factor of 1.0, I would say that the used area of the projector chip is 19.7mm x 34.9mm, whereby the 3chip indicates that a prism is among all three, which might change the size, but mathematically that should be the size at Focal length 18.2 (Zoom 1.0).

I can see that this would be useful for this kind of work. The Problem that showed up with this projector was that it had no LCD-“slide” size given (a sensor’s equivalence). It is sometimes difficult to get. Even for video cameras, when the sensor is set as a 1/2 inch chip, which was in the old days the enclosing glass tube, not the size of the “chip”.) So it is kind of the stopper in the idea.

If these values were available for all projectors, it would be easy to set things in math.  The simplest way to get the data is to take the focal length times 100 and measure the image width at that distance. This value divided by 100 should give you the “sensor-size”.

In fact, you can check with the Cinema 4D camera if the results are true.
Focal length 18.2, sensor 34.9
The shift of +/-30º is close to ~50% shift in the camera. (+/-44%v and +/-52%h).

Enjoy your project.

Got it, and thanks again Sassi, this was really extremely useful!