perspective skew in 3dsmax

[super gnu]

ok i hope i can explain this.


ive got a 3d model viewed from a perspective camera.. however i need to flatten it against the background (its for a pop_up book type effect) while keeping the apparent perspective the same.

i thought a simple taper or ffd would do it.. -rotate it to be flat on to camera then apply a taper to fake the lost perspective. however it does not work.

in photoshop, the perspective tool scales elements down correctly, but in max i get no scaling along the axis of the model if i taper.. see attached examples.



there is a hacky way to do it using soft selection along the model then scaling, but its extremely fiddly to get a true linear soft selection in max from one end of the model to the other.


any suggestions?

[kosso_olli]

Taper modifier on that piece of geometry?

[cheerioboy]

Why doesn't an ffd work? Might have to set it up so that the camera is straight on and the objects are rotated to match the view you want - then reset xform and ffd to flatten.

[super gnu]

hm.. im not sure if im not explaining very well.
i wish a facade ive constructed to look like it is receding in perspective from the camera, when in reality it is flat-on to the camera.

for this i need to taper it from one end to the other. if you look at the examples, in max, ffd (or taper) scale vertically along the length, but i get no reduction in scale of the windows along the length, they all stay the original width.

in photoshop, if i select a flat facade, and do a perspective transform, pinching one end scales the windows properly (although admittedly it makes them wider in the foreground, but this can be compensated for).


only way ive found to do it is to taper, then do a vol. select from one end, and apply an xform and scale horizontally.. this shrinks the windows horizontally, with the ones at the tapered end scaled more than those at the wider(i.e. nearer) end.

HOWEVER, the soft select in max has those annoying "pinch" and "bubble" settings, and it seems no value in those gives a proper clean linear scale from one end to the other.. meaning doing this method introduces a curve into the facade. in maya you can just choose "linear" for the fallof type, and it works cleanly.


does that make sense?

[AlexP]

how about a 4x4x4 ffd first to scale the window widths. Then 2x2x2 ffd to do the taper. Then at least you can control independently in the stack

[super gnu]

hm, not sure how 4x4 ffd is better than other options in the end.. i guess i can manually add more scaling progressively to each of 3 sections of model, but getting a smooth linear effect from one end to the other is impossible that way.. always get wavy edges in model and non accurate scaling of windows.


maybe an ffd 20x20 or something lol, but then i may as well manually shift vertices in original model lol.

[Vizioen]

If you have access to rhinoceros you can use the make2D command and reimport in 3dsmax.