#archway model prob
8 messages in this thread
Hi all,
I'm trying to find the least painful way of modeling something.
Got an arched walkway supported by columns.
The arch looks good. Had to keep shape steps up to 10 but it looks good.
now I want to take the lines that make up the lower part of the arch
and use that as a path for a trim piece that will be applied onto the arch
face.
So now I run into a two fold problem.
In order to get the trim to follow the arch I have kept the steps up (10).
But this puts a lot of steps in the horizontal trim also (^^^ area)
_______ ______
____| |______| |______(note vertical is actually curved.)
^^^ ! ^^^
I suppose I can 2d scale the extra vertices and weld them
The other problem is at ! where the arch begins and ends
I'm aware of the rescaling of the shape to compansate for the corner being
turned
(3D special effects book <g>)
If I use a step of 10 the profiles bang into each other when lofted
Somehow I need to pull the first interpolated step on the path away
from the inflection point.
I can only assume this means I must set my own vertices in the shaper
for both the arch and trim path and set step to 0?
If so what is the best way to station vertices along a curve?
If I have snap on, refine the curve, is the vertex put at the snap point
or at the math correct point for the curve data?
Or should I loft the arch trim seperate from the horiz trim and try booleaning
them?
Hate to model something and then have the bool fail <g>
Again ….Thanks for all the knowledge you guys keep providing.
Todd
>>Somehow I need to pull the first interpolated step on the path away
from the inflection point.
Try using Modify/Segment/Refine on the shape to place extra vertices where you
want them and reduce the Shape steps accordingly. This allows you to put detail
where you want it and keep the shape steps low for areas that don't need it.
Also, have you thought of lofting the trim with the arch?
– Phil
p.s. Gladd you liked the Special Effects tip <bg>.
<have you thought of lofting the trim with the arch?>
I'm not sure how I would do this.
The arch I have is in elevation view and I extrude it 2' in the Z in the lofter
The trim is more or less a have circle.
I only see how to build it using traditional carpentry.
How could I loft both together?
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Thanks again
Thanks for the chapter in the book
Todd
By lofting both together I was thinking you were lofting the inside of the
arch. This would work great if the archway was a defined by a change in
material or surface (cobblestone for example). The lofted curve could then be
allowed to intersect a much simpler wall form that provided a rough opening for
the smoother arch loft. Now, if you need the archway to be flush with the rest
of the wall you will need to use your method of just extruding it back. The
shape used for this exrtusion should then be used as the path for the trim .
Keep the path steps for the trim the same as the shape steps for the arch and
the two should align. Remember also that you can use 3D Display to show the
lofted arch mesh in the 3D Lofter for alignment purposes.
>>Is it typical that you must segment (acad=break) all these nice
arcs, either in autocad or 3ds, to have decent control
over vertex location? if so…I can't wait for NURBS <g>
Actually, every sgement in the 2D Shaper and 3D Lofter is a Bezier spline. When
you add vertices by using segment/refine you're not breaking the spline – just
adding detail where you need it. In general you should leave your AutoCAD model
as pure, long arcs and adjust them in the 2D Shaper. This ensures htey're as
smooth as ppossible and gives you the opportuinty to place the critical
transiiton points exactly where you need them.
– Phil
Just thought of another condition:
Here I have this really nicely built
autocad elevation. All the arcs are arcs
nice smooth double reverse curves, etc.
Is it typical that you must segment (acad=break) all these nice
arcs, either in autocad or 3ds, to have decent control
over vertex location?
if so…I can't wait for NURBS <g>
Todd
<In order to get the trim to follow the arch I have kept the steps up (10).
But this puts a lot of steps in the horizontal trim also (^^^ area) >
If I read you correctly, you should find that the 'Optimization' Button in the
3d lofter should work for you. If you turn this on before you loft your shape
into the 3d Editor you should find that the unnecessary vertices on the flat
lines are not created.
See page 16-14, 2nd paragraph in the Tutorials book to see one example of how
it is used.
See page 16-12 in the Reference Manual to see a lofted object with and without
optimization on. This seems to most accurately reflect the problem you are
seeing.
Hope I am on the right track with this….
Good luck, Kevin
Hello, it's me again. Just wanted to let you know that those page numbers refer
to the R3 pubs…
See Ya! Kevin