[Plugin] TrueTangents v3.0

simon le bon

@tig said:

v1.9 now has a sub-menu in Plugins 'Tangent-Tools...' that accesses the 5 tools...

this tool is a ruby!

@simon le bon said:

I'm a little bit disappointed by the fact that depending on the radius is, the tangent lines cannot join perfectly ( certainly due to segmentation of the circles)

but that's the whole point
the cpoints are placed in the correct place so you can the draw (or redraw) the arcs at the true position. Hence - true tangents

I'm not sure to understand right to be correct !!

Is this the right way?

Am I correct if I follow the tangent inference this way?

The possibilities are very numerous

simon

jeff hammond

the const. points show where a real, non-segmented circle would cross at key points.. these are basically layout tools for people that need real world measurements when building arcs and if your use of SU is mostly to draw things that are organic and/or don't need to be 100% precise then you probably have no real need for TrueTangents (ie, if you're drawing a building simply for representational purposes then it doesn't matter if a wall is 3/4" too thick.. if you're drawing a building that is going to be built in real world using the SU print, then it better be exact or there's going to be a lot of cussing on the jobsite)

if you really had a need for this plugin then i don't think there would be any question about it's usage.. you would see its benefits immediately.

jeff hammond

[btw, it's the top of a pool.. a down&dirty render of what's happening with that drawing]

jeff hammond

for example ---
without using truetangents, modify this SKP to correspond with this jpg.. the stuff in red is missing in the attached .skp.. (and it is possible to do without TrueTangents but it's a major headache)

if you decide to do this with TrueTangents, you would use the 4th addition.. Tangential Arcs [Arcs+Line]

tt_quiz.skp

jeff hammond

here's a video showing how you might use truetangents to finish that skp.. (fwiw, i'm using didier bur's arc ruby to draw my arcs.. included in that is a 'center + two points' option in which you select the centerpoint and the two ends of the desired arc.. all of these points are given to me via truetangents)

[flash=680,378:1hkwq6mh]http://www.youtube.com/v/OWsg1q4HcKU&hl=en&fs=1&" type=[/flash:1hkwq6mh]

pilou

Cool video!
Yes that is tricky and thanks to Tig for this new true gem!

TIG

@unknownuser said:

here's a video showing how you might use truetangents to finish that skp.. (fwiw, i'm using didier bur's arc ruby to draw my arcs.. included in that is a 'center + two points' option in which you select the centerpoint and the two ends of the desired arc.. all of these points are given to me via truetangents)

Thanks for your tutorial - your are better at explaining my tools than I am !
FWIW, You can draw various Circle and Arc formats with my 2D Tools - similar to the one you describe... but perhaps more SUp-like ? The TrueTangents' Cpoints suit 3-point Arc/Circles...

simon le bon

Thank you Jeff for your explanations.
Things are much clearer to me now.

One of the points which was missing to me was the necessary tool: arc by three points

This Didier Bur tool can be found on Ruby Library Depot under: Geometry - DrawingHere or in french Here.
We can find on the same place auto_centerpoint_v10.zip by Jim Foltz or the one you are using:Arc Centerpoint by jim

And also:

@tig said:

FWIW, You can draw various Circle and Arc formats with my 2D Tools - similar to the one you describe... but perhaps more SUp-like ? The TrueTangents' Cpoints suit 3-point Arc/Circles...

[Plugin] 2D Tools v3.6
and 2D Tools Guide
(Dear TIG, I still not have found time to watch this exciting tools set)

@unknownuser said:

if you really had a need for this plugin then i don't think there would be any question about it's usage.. you would see its benefits immediately.

I hadn't thought yet with the problem of "true" tangents. You have opened my eyes on this. On the another hand, it is not easy to think and draw a predictable tangent (true or "false") with SketchUp. So, this set of Tig's tools is a gift, even for drawing "organic shapes".

simon.

jeff hammond

@simon le bon said:

right! that's it

avya

i thank u so much... gonna make a try for this one.

toto ete

thank u for this great plugin TIG!

Hey jeff how do you make the pool? the video end to soon.

jeff hammond

hey toto..
here's the basic process i've been using for this situation (i simplified some of it so it wouldn't take too much time but hopefully the method will come across).. there are some much simpler ways of doing something that sort of looks right but once you get in there for actual dimensions, it doesn't work out.. i build these out of wood so i need accurate dimensions (for skateboarding.. i need to make certain shapes to make it rideable).. the main plugin was fredoscale's 'scaling with orientation'..
also, i'm always interested in refining my drawing methods so if anyone has any ideas, feel free to tell me [or better yet - TIG, how's that two rail ruby coming along ]

[shown at 8x speed.. original was 21 minutes]
[flash=704,424:38dt7o97]http://www.youtube.com/v/S52C0nc5NmQ&hl=en&fs=1&[/flash:38dt7o97]

here's another method i use sometimes if i want a radius at the bottom and only one bend instead of following a top radius.. this one focuses around fredoscale's bend tool and the first 45 seconds of the video is showing me setting up for that bend.. making a custom arc so all the vertices match up and make a clean mesh once the compound bend is applied (note at around 1:30 in the video that all of the bend tool's slicers line up with the mesh... if you don't do this then make a curve on top of another curve, you'll end up with a bit of a mess which is hard to take the drawing further)

[shown at 3.5x speed.. original was 6 minutes]
[flash=704,424:38dt7o97]http://www.youtube.com/v/fuRo6GPh_Hw&hl=en&fs=1&[/flash:38dt7o97]

toto ete

hey jeff, thanks for adding more videos. are you having custom toolbars for every project?
i love your work style and i must say again a big thanks to all ruby coders for making such things possible.

simon le bon

Dear Jeff,

I come back again on this method you develop into the previous video(the first one).

Very foxy, indeed. I keep the link apart

Can I make a critique on the video itself !

Some few editing, pointing milestones and resizing the long sames actions are preferable to this speedy solution. Witch we drive us to come again 5 or 6 times on the same rocket transition.

++simon.

Ricco

Thank for this TIG
I think it will help me in my work,
Now, i'm gonig to watch tutorials,
Bye Jeff
Ricco

dermotcoll

Thanks TIG - I look forwardto using this in my modelling.

Slainte

Dermot

simon le bon

Dear Tig,
sorry for disturbing!
I experience some difficulty with "Common Tangents"
After various tries, I haven't found what can be the point which make the plug sometime not working!

Maybe an idea?
simon

TIG

So, to recap... you have discovered certain combinations of circles that won't display 'common-tangents'?
Looking at you image there seems nothing untoward. However, are all of these circles 'co-planar'? If they are not then they have no 'common-tangents'... I can't get it to reproduce unless I lift one of the circles up by a tiny amount (0.1mm) then it fails. The one with partial clines is a mystery...
To check this move the problem circles up in the z a large amount then draw a large face at z=0 under the circles and use the Sandbox Drape Tool to ensure they 'stamp' onto the face. Erase the originals and the rest of the unwanted face. Retry the common-tangent tool to see if they now form...
Could you send your problem skp to me by PM rather than clog up this thread ?

TIG

Here's v2.0 http://forums.sketchucation.com/viewtopic.php?p=160780#p160780
It has a tolerance added to the check on pairs of arcs' co-planar-ness: now pair of arcs that are not quite co-planar are still processed successfully...

simon le bon

Hurra!
I don't experience no difficulty anymore. Top strong!
Thank you TIG