Perspective Projection Intersection Object

[FabienM]

Hello,

I work on SU 8.
I have search on the forum and in the internet,
but i don't find an answer to my question/problem.

I'm searching a way for projecting an object in a perspective mode,
( like if the object start from one point - the eye or the camera - and grow up to infinite ),
and this " object perspective projection " can make intersections with differents plans in space,
and finally i can obtain the deformation layout of the object projection on each plan ?

I'm not sure that my explanation is very comprehensible,
then i make a quick drawing.

In my example below :
The object projection is the text " Harmony ",
i put two position of it in the projection cone, a near one in white, a far one in black.
I draw an axis through the " M " caracter, and two lines on each side to represent the aperture of the lens.
The differents plans in space are in colours ( Red, green, blue, pink, yellow )
The first image file is like an bird view to understand the space, the second one is from the point of view.

I would like know, how project an object with a perspective angle, and make intersection with the differents plans ?

I saw the plug-in from Didier Bur - Projections version 2a -,
it 's great but work only in a parallel mode ( not in a perspective mode ).

I don't know if it's possible to extrude an object in a perspective mode,
from one point to infinite according to an angle in X-Axis and Y-Axis ?

Some persons are talking of " Projection Mapping ",
but it's seems to work with some texture / UV, and run on another software than SU.

In short, i'm a bit lost !

Thanks in advance for your help and yours ideas.

[JQL]

What's really easy to do is to project a photo into geometry. This is done with Match Photo wich you can find on Window > Match Photo.

What it does is that it let's you align your model with a photo using 3 point perspective and then, in the Match Photo window you have a button to project texture from photo into objects. After the photo is projected on the objects I suppose it would be fairly easy to make the countour.

EDIT:

Take a look at this plugin from TIG.

http://sketchucation.com/forums/viewtopic.php?p=273654#p273654

It can be made to work with the following process:

• C point + geometry + plugin
• Really long lines
• Generate triangles in the end of each pair of lines
• Select all triangles
• Use context menu's "intersect faces..." on the selection (and choose the option available)
• You now have generated the intersecting lines between the triangles that form the perspective "piramid" and the model geometry.

[FabienM]

Hi JQL,

thanks for your help and your edit,
i more interest by the plugin from TIG,
than by the image projection
( that's seems if i understand well, you must re-drawing the image projection for keep the intersection ).

I try the plugin.

[pbacot]

What's the end result. A plugin? or do you want to see views of the word as it would appear in various planes cutting the perspective projection?

---

[FabienM]

Hi pbacot,

i would like to extrude in a conic ( perspective ) projection ) my object ( the text ),
and obtain the deformation of each part of this text,
on each plane where the object projection ( the text ) interact with the planes.

Hope it would comprehensible ?

[pbacot]

I did those by scaling the 3d text to be super long (or deep). and then enter the group and scale one end to be super wide and high. Then intersect with section cuts or you could interersect with faces. Don't know about camera apertures and infinity though.

[Dave R]

Didn't ThomThom or someone do a ray tracer plugin that would do this?

[FabienM]

Hi JQL,
i try the plugin,
it's a first good track.

I'm not sure understand when you talking about :
" *- Generate triangles in the end of each pair of lines

• Select all triangles* "

I have selected the projection line and one face,
and like this i have the intersection selection.
After i must connect each end of line on the face,
to redraw the shape of the letter,
it's a little paintful, take time, and not exactly the original shape of the letter,
but that allows to have a result.

In SU,
there's not some tool could be connect a face with an another face with various size and orientation ?
( maybe connect and extrud the small white text with the big black text )

Thanks for your help.

[FabienM]

Hi pbacot,

thanks for you help,
it's interest to deform the text,
but i'searching more a solution with projection and intersection with faces,
or maybe the possibility to join 2 faces of the same object ( identical numbers of lines... )
in two different sizes and orientations, and after intersect this new volume with the faces.

@ Dave R : I don't known what is ThomThom ?
Edit : Ok, it's a developper but i don't find some plugin to divert.

Edit : Another way is to extrude longer the text, go inside and select the front side and rescale,
like this the text is extrude in pyramid.

[Dave R]

Ray Tracer

This might work. I haven't time to work on it right now but you can give it a look.

[driven]

post your skp and we can try and offer solutions...
john

[pbacot]

@fabienm said:

Hi pbacot,

thanks for you help,
it's interest to deform the text,
but i'searching more a solution with projection and intersection with faces,
or maybe the possibility to join 2 faces of the same object ( identical numbers of lines... )
in two different sizes and orientations, and after intersect this new volume with the faces.

@ Dave R : I don't known what is ThomThom ?
Edit : Ok, it's a developper but i don't find some plugin to divert.

Edit : Another way is to extrude longer the text, go inside and select the front side and rescale,
like this the text is extrude in pyramid.

I think that's what I said.

---