Sketchup is Inacurrate???

jeff hammond

I just used the given geometry, I didn't redraw the straight edges, [ I wasn't doing it as a pissing contest (@ that point)

ha.. i'm not pissing contesting either.. we were just talking about accuracy for the past week or so in the thread so i think it's important (for the sake of this particular discussion at least) to be accurate..

@unknownuser said:

I know you use 3pt Arc.. and that's exactly why I did as well.

check out this plugin.. i did this huge workaround 10x faster than it took me to do the sketchup-only work around..

(no audio)

http://www.youtube.com/watch?v=paI2eEn6CW4

(**includes bonus footage of su's spazzed dwg importer)

that's the same model saved right after i quit ishowU_ing

that's not a plug in.. it's a plug out..
why would i want to use sketchup at that point? i wouldn't.. that was kinda my whole point up until page 20smthng when jbacus basically summed up the future regarding circles in sketchup..

i guess now i'm just talking because i'm a nerd like that

@unknownuser said:

All I was trying to point out was if we can draw it that 'close to being' accurate, then the engine didn't need changing, it just needs exposing in an easy to use tool, either as an additional option or as a new tool.

The biggest thing that annoys me [other then you, of cause!], is the 'Offset Tool' doesn't snap on the arc point, so you can't be accurate with it.

nah.. the engine needs changing.. it needs to be smarter regarding circle.. there is no new tool that's going to solve this because it's the whole app being affected-- not just the offset tool.. teach sketchup some basic circle stuff and a whole slew of problems will start disappearing.. otherwise, all you're going to do with a new tool is pile more crap on top of a weak foundation.. fix the foundation .
(of course.. that is simply my opinion.. i truly understand that many people couldn't care less about this)

re: annoying..
i annoy myself with this stuff too.. like i'm bothered that i'm even bothering any longer.. i wish i could stop but i haven't found the switch yet

DesertRaven

@unknownuser said:

nah.. the engine needs changing.. it needs to be smarter regarding circle.. there is no new tool that's going to solve this because it's the whole app being affected-- not just the offset tool.. teach sketchup some basic circle stuff and a whole slew of problems will start disappearing.. otherwise, all you're going to do with a new tool is pile more crap on top of a weak foundation.. fix the foundation .
(of course.. that is simply my opinion.. i truly understand that many people couldn't care less about this)....

I'm sure there are plenty of folks out there who wouldn't care about these issues, mostly the ones used to how SU works, because they are set in their ways.
Many have a problem with changing things to the better and settle for what they can get.
I think it would be a shame if SU would not evolve and I do see the great potential.

I'm very happy that it did evolve to where they added the solid tools. These are a great asset in today's world of e.g. 3D printing and a step closer to making us build more accurate models. (and requires SU to be even more accurate)
So as we progress, the requirements and standards will also become higher. To not improve would be going backwards. I, for my part, would love to keep working with SU in a world that changes fast and be able to deliver great and accurate work for my clients.

pilou

@Jeff
You must return make a little visit to the Moi Forum !

jeff hammond

@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 )

pilou

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)

gilles

Tangent arcs.

Tangent arcs_V6.skp

Tangent arcs_V6.png

pilou

Robust!

And if for any reason I don't want elongate in straight line the piece of road on the right ?

TIG

@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...

driven

mitcorb

I have been following this thread. And I care, if it is do-able.

pilou

@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

jgb

@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.

This is a sketch of a solution, not an accurate drawing.

jeff hammond

@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..