#Mirror, mirror on the wa
18 messages in this thread
ll…, or, more precisely, on the floor. Do you know of a strange behavior of
flat mirrored surfaces resulting in mirror images that are physically
impossible? Please, let me explain this.
I have modelled the logo of my company as a lofted text object sitting
on a plane in a straight line. The surface of the plane is flat mirrored as
well as the front faces of the text which are perpendicular to the plane
surface, of course. Plane and text are individual, separate objects. The mirror
image in the plane is ok. The odd part is the mirroring in the text faces. You
can see the _first_ letter mirrored in the _last_ letter (which is across the
whole screen (er, the distance of reflection, not the letter)) and, even
better, rotated by what seems to be 90 degrees.
Is there an explanation for this naughty (tsk! tsk! tsk!) behavior,
maybe buried deeply in the theory of speeded up flat mirror mapping? Or do you
know a better workaround than mine (which is to render the picture twice; one
with the last letter hidden, the other with the first letter hidden; then cut
and paste both together in PhotoStyler)? Or do I have to reflect upon the
nature of reflections?
Volker
PS: Why is it that my messages keep getting longer and longer as I'm writing
them? It MUST be the ozone hole…<G>
Are you using a mirror on the text faces AND the plane? If so, you've got to
be very careful about exactly how you apply all those mirrors. If you screw up
just a little, you'll get exactly the effect you're describing (the wrong
reflection in the wrong mirror). Also note that flat mirrors aren't recursive,
so don't expect to see the mirror in the mirror.
– G
Gary,
>> Are you using a mirror on the text faces AND the plane? <<
Yup. Sure.
>> If so, you've got to be very careful about exactly how you apply all those
mirrors. If you screw up just a little, you'll get exactly the effect you're
describing (the wrong reflection in the wrong mirror).<<
Ah, could you please elaborate a bit on that? I think I have read the
fine print in the manual (yes, the faces of one single object are coplanar (I
hope it's called 'coplanar' I just have the German version…); no, the objects
don't intersect; and so on), but as a mere mortal (even with tentacles…) I'm
subject to ignorance, and I haven't finished reading the Inside 3DS4 book
yet…
To tell you the truth, what I did was as follows: For a long time only
the two up-faces of the box which serves as my 'infinite plane' have been
assigned a flat mirror material – the text was done first in a automatic
reflection then in a reflection mapped gold material. Then one day I thought:
"Hmmm. How would the text object look in reality when made of gold?" That was
when I decided to flat mirror the text faces too. It was done in four steps:
– One. The entire text was only one object (all letters were combined to one
shape when imported to the lofter) and I selected the front faces only (in the
3D editor) and assigned my flat mirror gold material to them. Result: the first
letter was reflected in the last. I thought: "Hmmm. Obviously the flat mirror
doesn't like to be expanded across several elements." Therefore I came to step
number
– Two. I detached all the letters to single objects, selected the front faces,
assigned my flat gold to them. Result: first letter reflected in last letter. I
thought: "Hmmmm. Perhaps the flat mirror doesn't like to be combined with a
normal material." which led me to step
– Three. I selected the front faces of my text objects and cloned them to
single objects of their own, assigned flat gold to them and… Bingo! First
letter could be seen in Last. I thought: "Wellwellwell. My obvious fault is
that I always selected the front faces of all letters together. All I have to
do is step
– Four." I assigned my flat gold to the faces of each letter individually. The
result you probably won't guess: Yeah, I had to take step
– Five. Cry for assistance in the ADesk forum…
>> Also note that flat mirrors aren't recursive, so don't expect to see the
mirror in the mirror. <<
I never expected to see the reflection of the reflection of the
reflection in the reflection. Nah. Imagine my surprise when I saw this mirrored
letter thing!
Volker
At this point, you'll have to enlist the aid of Jonas (or another kind soul) to
go over the file and steps with you to show you exactly where you went wrong.
(I just don't have the time… sorry.)
– G
Gary,
>> At this point, you'll have to enlist the aid of Jonas (or another kind soul)
to go over the file and steps with you to show you exactly where you went
wrong. <<
Yeah, sure, will do. I just thought you could tell me on the fly the
Most Disgusting Things One Can Do To Flat Mirrors which I was overlooking.
>> (I just don't have the time… sorry.) <<
Hey, absolutely no need to be sorry. I'm amazed by your omni-presence
and ever-answer-readiness over here anyway. I think it's time to thank you for
your assistance (and your sense of humor… ozone…)
Volker
Volker,
What most do with flat mirroring that gets them into trouble is to first apply
the material at the object level, and then, when they've realized their error,
go back and reapply the same material at the face level — while leaving that
same material _also_ applied to other faces in the object. Confused? I noticed
in the message that you did a lot of face detaching to try to get things
working. This shouldn't be necessary. Just make sure that your one flat-mirror
material is assigned to _only_ coplanar faces in the object, and that a
different material is used for all other faces. It's also possible that what
look like coplanar faces in your text have been modified so that they're no
longer coplanar. This would also mess things up. You might try hiding that text
and lofting some new text, then reapplying the material cleanly and seeing what
happens.
(I don't have any time either, but it's easy to toss out theories. Just don't
expect any follow-up. <g>0
– Jack
Hi Jack,
for a moment I was thinking you've got me onto the right track. As
you've said, I've been tampering around with the front text faces quite a lot
and I _never_ relofted my object. Well, today I did what you told me, and
"Uh-huh! Now whats this? Beveled shape invalid?" And then I did remember and it
came into my mind like hot lava that indeed I was thinking that a beveled edge
would look nice on my text. Resetting the bevel path was a matter of half a
second (or less) and then I lofted my text, selected the front faces (and only
them), applied my flat mirror gold and rendered the scene. Guess what
happened… boohooooo! The first letter is mirrored in the last one. So anyone
trying my project file: don't triumph too early, killing the bevel in my
lofting dosn't do it (alone, that is…)
Now I'm gonna try to build the whole scene from scratch including all
materials. If I'm able to recreate this effect I'll cry out loud again…
And, Jack, thanks for your support in spite of your time being so
short.
Volker
Good luck, Volker. Sounds like "from scratch" is your best approach at this
point.
– J
Hey… no problem. I love hanging out here, and just wish that I could clone
myself so one of me could be here more… Unfortunately, inventing the future
is _really_ hard work. <g>
– G
Gary,
try the Shift + Modify/Gary/ScaleTime option for your problem… <g>
Volker
Tried it. (crashed the system)
– G
I know. Ole Pharlap just doesn't tolerate multidimensional operations. Wait for
Release 5, maybe NT will handle these better… (but then, maybe Santa will
take your tooth at the next Easter)
Volker
Hi Volker,
<< You can see the _first_ letter mirrored in the _last_ letter (which is
across the whole screen (er, the distance of reflection, not the letter)) and,
even better, rotated by what seems to be 90 degrees. >>
Hmm.. haven't heard of this one. Could you please upload an example of this
behavior to the library please?
jonas[adesk]
Hi Jonas,
yeah, sure I'll do, the zip is small enough to be no bother for anyone.
I just 'contribute' it as usual? Or should I mail you this project privately?
Volker
Hi Volker,
<< and I haven't finished reading the Inside 3DS4 book yet… >>
Please do. It's very good 🙂
<<..'contribute' it as usual?..>>
The recommended procedure would be..When you have a reproducable case that you
think violates the documentation, upload a *.3ds file along with any addition
text that helps explain the problem, zipped, to the library with the keywords
"Problem File For Autodesk Review".
jonas[adesk]
Hi Jonas,
I entirely agree with you on the Inside 3DS book. It's fantastic how
the authors put their fingers onto strategies which were nagging at my mind but
never made it to my consciousness. I'm glad to have the book.
As for the zipped problem file, it's on its way.
Volker
Hi Volker,
<< how the authors put their fingers onto strategies.. >>
Have you had a chance to dig into the scripts found on the CD yet? They happen
to be my favorite part ;->
jonas[adesk]
Hi Jonas,
< dig into the scripts >
No, not yet, but I'm constantly working on getting through the book.
I've learned to appreciate the possibilities of keyscripting before, though,
when I was facing trouble producing a linear zoom effect. Writing a little
script helped me out of my sort of situation, like, totally.
Volker