Complex 3d Space Question

[Mylenium]

Neither is there a simple algorithm nor technique nor any magic plugin. The simple truth is that you do not have access to the actual pixels of a layer or mask shapes and thus never exactly get the proper dimensions on irregular shapes. I believe a while back Dan posted some simple code for a projection matrix based on using the acos() function, maybe you can dig it out and work from there. Other than that – like they say in “Battlestar Galactica” at one point: “Mark 1 eyeball.” ;o)

Mylenium

[Pour Myl

[Andrew Kramer]

https://forums.creativecow.net/cgi-bin/new_page_wrapper.cgi?forumid=2&page=https://www.creativecow.net/articles/kramer_andrew/3dcompositing/index.html

If the camera is orthographic then the effect of having a camera will certainly be lost. In the tutorial above, I simply resize the layers to the comp size before proceding. Good Luck,
Andrew Kramer

[Dan Lachevre]

Hi Guys

Thanks for the suggestions. You guys are always helpful and Andrew, your tutes are great. Hope they’re paying you the big bucks!

Had a look at the two suggestions but Dan’s expession entry was a bit beyond me and Andrew, your tute isn’t exactly what I mean.

There is a great experimental project by MK12:

https://media2.mk12.com/v5_qt_html/2001/infinity.html

that does exacly what I mean and I can’t work out how they’ve done it. It is best displayed at 1’37” where as the camera moves we can see the radioactive guy is actually shattered over the Z axis. It doesn’t appear any of the layers are moving so how does everything match so perfectly. I’ve come close by manually moving sections and merely eyeballing it but nothing close to this degree. It is obviously easier with less z movement and a less distorted lense but there must be an easy way of doing this.

There is some great 3d stuff in the clip but it is this 2d/3d technique that is the most interesting.

Danny

[Dan Ebberts]

This seems to work. It assumes your camera starts out on the comp’s z axis. Start with your pieces arranged at z = 0. Add a Slider Control to each piece and set the value to 100. Add this expression for Positon:

cameraPos = [thisComp.width/2,thisComp.height/2,-888.9];
zControl = effect(“Slider Control”)(“Slider”);
v = (value – cameraPos)*zControl/100 + cameraPos;

Make sure the z value in the cameraPos variable matches your initial camera z position (mine was -888.9);
Add this expression for Scale:

zControl = effect(“Slider Control”)(“Slider”);
value*zControl/100

Adjust the sliders – values smaller than 100 move the piece closer to the camera, greater than 100 move them away. There should be no apparent change in position or size as you adjust the slider – it only shows up when you move the camera (or change the view).

Dan

[Mike Clasby]

It works… Great.

Thanks dan811 for asking the question and Dan007, I mean Dan Ebberts, for answering.

[Andrew Kramer]

WOW! That’s a mean script. Excellent.
Andrew

[Dan Lachevre]

A huge thanks for that Dan! That is awesome. I have been looking for a way to do this for ages. Unfortunately my ability with expressions is pretty limited.

This forum is always such a great source of help!
Thanks again to all!