Sketchup is Inacurrate???
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@unknownuser said:
@Jeff
You must return make a little visit to the Moi Forum !
i did.. michael pretty much told me I'm dumb for using sketchup
not in a way that says anything bad about sketchup but more in a way of..
"hey, it's not sketchup's fault for not working that way.. it's your fault for trying to use it that way.. "
(actually, he didn't say any of that really... it's just the feeling i got after reading.. but if he did say exactly that, i'm thinking i agree
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Despite of all that, what is the best connection between 2 parts of any inclined roads on a flat terrain?
(in any progs of course just in theory with same width on the path)Compass+ Protractor + Set Square + Ruler
Arc circle + tangency
Blend + tangency G1, g2, g3...+ Bulge
Fillet G1, g2, g3...+ Bulge
Sweep variation
Conics
Offset of one jointure
From a joined yellow line then propagate a perpendicular width segment
...
(here connection wanted on the top)
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Robust!
And if for any reason I don't want elongate in straight line the piece of road on the right ?
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@unknownuser said:
Robust!
And if for any reason I don't want elongate in straight line the piece of road on the right ?
You then need to shorten the road on the left AND increase the radius !
There can only be one circle of a given radius that is tangential to two lines drawn line this, and it will determine its own 'kissing' points on these... Its center is always on the bisector of the edges' angle, and the circle can slide along this, and therefore depending on its radius that will fix the center, because it must be the radius away from both edges when measured perpendicularly from them... -
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I have been following this thread. And I care, if it is do-able.
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@unknownuser said:
You then need to shorten the road on the left AND increase the radius !
Robust again
So if for any reason I don't want elongate or shorter in straight line pieces of road on the left and the right connection with tangency is impossible ?
Said a "plumber" who has not straight tubes but any curvated one
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@unknownuser said:
Despite of all that, what is the best connection between 2 parts of any inclined roads on a flat terrain?
This is a standard "OGEE" Curve problem of joining 2 non parallel roads.
Did it in High School (that's 53 years ago
) with pencil, compass, slide rule, protractor and ruler. No such thing as a pocket calculator then, let alone Sketchup.But damned if I could remember how I did it!!!
Played in SU for 29 min and got nowhere.
So the attached drawing is a "Sketch" of what the solution would be.
Not calculated, just by eye.
The "road" rectangles are drawn overlaid on Pilou's ROAD.JPG.
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@unknownuser said:
Despite of all that, what is the best connection between 2 parts of any inclined roads on a flat terrain?
(in any progs of course just in theory with same width on the path)Compass+ Protractor + Set Square + Ruler
Arc circle + tangency
Blend + tangency G1, g2, g3...+ Bulge
Fillet G1, g2, g3...+ Bulge
Sweep variation
Conics
Offset of one jointure
From a joined yellow line then propagate a perpendicular width segment
...
(here connection wanted on the top)in sketchup, you can use bezierSpline to get a tangent b-spline for one connection.. as far as accurately offsetting that curve, i don't know how to.. the maths go beyond my knowledge at that point and i'd rather just have software do the proper calculations for me
(and actually, i don't know the maths to even see if the sketchup drawn b-spline is in fact correct.. and this is an instance where, to me, it's required that i'm using an app that i can fully trust to give the right solutions.. goes back to what i was saying about knowing the numbers.. i don't know the numbers here and neither does the app so i'm screwed..)
• draw an extended line to the one you would like to connect tangentially to..
• using uniform B-spline set to an order of 4 at least, make 4 clicks, (first tangent point, end of it's extended line, end of the other side's extended line, second tangent point)but assuming that curve is in fact correct, i have no idea how to proceed with offsetting properly (as in, arcs are easy to understand.. these types of curves?.. well, let's just say i was never taught about them in school..
but hey, in sketchup, i could definitely come up with something that looks ok..
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Seems very cool too!
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@jgb said:
Played in SU for 29 min and got nowhere.
or, using the ArcBlend command, you'd play with it for 29 seconds and see all possible solutions..
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@unknownuser said:
Seems very cool too!
oh. i thought that was a standard approach in france.. don't all the roads look like this over there?
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Sorry Driven but already done
http://sketchucation.com/forums/viewtopic.php?f=15&t=44142&start=480#p453462But
@unknownuser said:pilou wrote:
And if for any reason I don't want elongate in straight line the piece of road on the right ? -
Damned: Imperial measures can be readable as hours minutes second!
(maybe it is ? )The funny thing is that tool who is named in Fance "pistolet" (pistol, gun)
is named on the new world a "French Curve" I don't know why! ?
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a more serious reply... for an even curve from both directions.
johnedit.. took the skp off as it's a repeat of earlier offer.
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@gilles said:
With bezeir classic + component stringer + polyline= tedious.
here's one done in rhino then brought into sketchup and segmented.. it looks as if this version has the 5m crosslines perpendicular to the curves whereas yours look to be leaning..
thing is, i can't figure out how someone could calculate where exactly perpendicular to a curve like this is in a polygon app.. have a look at this .skp and see if you can find any sort of method/reasoning to achieve it manually..
as far as i can gather at this point, the best we could hope for in sketchup along these lines would be some sort of educated guess ?? (actually, i bet it's possible to do it accurately with a segmented modeler but at that point, the app would have enough info to display the true line so why bother segmenting it)
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.
here's another example of sketchup acting in an intelligent manner with regards to its arcs..
if you use the arc tangent snap on another arc, it acts appropriately and accurately..
then explode the other arc and you'll see it gives a different result (the correct result for that situation)..i was a bit surprised to see sketchup handle this properly (it's different than other 'smart' examples i've given because in this case, sketchup is correctly identifying whether pre-existing geometry is an arc or a series of edges (even though the look identical) then reacting accordingly
but it's a good example of how sketchup could also be identifying whether the user has an arc or edges drawn prior to offsetting/followme_ing and reacting correctly..
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