[Plugin] Extrude Edges by Rails

ionandre · 28 Nov 2009, 08:23

Just noticed this:

with a simple straight line(curve) used as profile you can loft 2 closed rail curves directly (poligons) as well, but if use an arc as profile the result is a twisted loft. Why that?

TIG · 28 Nov 2009, 09:47

It takes the nearest points of the rails to place / adjust the profile.
Split the square's edge nearest the circle at it's center.
It should then not twist ?

ionandre · 28 Nov 2009, 18:17

@tig said:

It takes the nearest points of the rails to place / adjust the profile.
Split the square's edge nearest the circle at it's center.
It should then not twist ?

Thank you for the advice, however It seems no possible.
By the way I can ever achieve the good result with the previous method.
Maybe it would be nice an option to set the starting point.
It could work well in conjuction with tool on surface I think.

By the way I think your plugin is quite revolutionary.

thanks again.

Ionandre

TIG · 29 Nov 2009, 20:07

Sorry, I don't think my last explanation was very clear.

As explained in the Tool's notes... if the Profile touches a Rail then that fixes the Profile's 'snap-point' on that Rail: it is the safest way to fix what's made - otherwise you can be surprised - like this 'twisted' extrusion.
So it if touches both Rails then that fixes the Profile without twists - sorted.

But like in your case - if the Profile doesn't touch Rail-1 then the snap-point for the Profile on Rail-1 is taken as the point nearest to the end of the Profile - unfortunately in your case Rail-1 [the square] has 4 points that are all 'nearest' to the centred Profile's start [this is after the Rail is sub-divided into parts to match the Circle]. Therefore the Tool guesses at the start of Rail-1...

Next, as in your case - if the Profile doesn't touch Rail-2 then the snap-point for the Profile on Rail-2 is taken as that point nearest to the end of the Profile; however, in your case it's a circle so all of its Vertices are equidistant from the Circle's center [the Profile's other end] ! So in this case it takes the snap-point as the one nearest to Rail-2 - and that's the bottom of the circle...

Now the Profile is snapped to that point and a point on Rail-1 - which can be guessed as any of 4 points - giving a 4:1 chance of a twisted extrusion being made...

Simple fix... the Profile's path is not change if it is relocated... So Move the Profile so that it's end is very near to the bottom Vertex of the Circle-shaped Rail... Pick that, then Pick the Circle-shape as Rail-1 then Pick the Square-shaped Rail... It should make an non-twisted extrusion.

Another way is to Divide the four edges of the Square-Rail into halves [so it then has 8 segments], then Move the Profile so it snaps to the Square's edge's mid-point that is nearest to the bottom of the Circular Rail, and then Weld the Square's 8 segments into a Curve... Run the Tool, Pick the Profile, the Pick Square-Rail, then Pick the Circle-Rail... Again it should make an extrusion that's not twisted...

xrok1 · 29 Nov 2009, 20:59

Tig, would it be possible to make your plugin so one could lasso select the rails, eliminating the need to weld them ahead of time? i ask because it seems the weld script is kind of finicky and sometimes requires some effort to get the desired results.

TIG · 29 Nov 2009, 22:56

Why is Weld so difficult - select the edges, weld them [answer No to any prompts], done ?

You'd need to select the edges with your method anyway - my plugin needs three curves - therefore weld some edges to make one if you need it...

xrok1 · 30 Nov 2009, 04:27

weld doesn't always work, sometimes i have to do some creative things to get it to work, ie allow it to make a face then delete or explode parts of the curve then weld!

jeff hammond · 30 Nov 2009, 06:12

@xrok1 said:

weld doesn't always work, sometimes i have to do some creative things to get it to work, ie allow it to make a face then delete or explode parts of the curve then weld!

yeah, i get that too.. especially if i'm far along in a model and have used a lot of rubys prior to trying to weld.. i just save the file then reopen it.. weld seems to like the fresh start

ionandre · 30 Nov 2009, 09:54

Ok, now I have clear how it works. thanks.
Best option for me is to divide polygons in two welded halves. It doesn't take too long.
Moving profile can be an option for a different result. I mean the extrusion is good but with a different form.
By the way for what I have experimented until now, the last version (3.0) of the weld tool always work for me. I did notice some problem only with old version of this plug-in.

TIG · 30 Nov 2009, 09:57

I you are trying to weld bits of curves together into one bigger curve then right-click context menu explode-curve first so that weld has raw edges to work with.

Weld will sometimes make curves with unexpected vertex order - another fix for that is to select the curve and groups it then explode the group, often that will sort it out. Again if the curve has no edges using edit-cut and imemdiately paste-in-place can reorder the vertices correctly...

If you think about it EEbyRails using some weld type algorithms to sort vertices for mesh-making, these can occasionally [mercifully very rarely!] go wrong too. If the model's data-base is a little confused picking separate edges for EEbyRails would produce as much flakiness as welding them into curves first off !

For the foreseeable future EEbyRails will require three curves to work (or two if rail1==rail2)...

dicoy88 · 1 Dec 2009, 19:22

why is it that when i try the plug in this is what i got, no success at all.

JClements · 1 Dec 2009, 22:18

Pretty Slick! Thank you, TIG.

1- Debabilizer. I am not sure but I think it is causing SU to load a lot slower. If it is not absolutely necessary, could a test be done in which it is not used to see of SU loads faster?

2- See attached. I used the colored edges to produce the top part of this swept wing. Then used joint-push-pull to creat the lower surface and then deleted extruded "side-surfaces" made by J-P-P. I wanted to see if make a rounded "lip" and along the two surfaces using Edges by Rails, but this is as good I could get it (I tried various combination of subdividing the edge rails, but the results were worse in most cases). How could a convex lip be formed along the edges of the wing?

wing.skp

TIG · 1 Dec 2009, 22:30

I've tested DeBabelizer myself and I seem to get no significant speed affects - db only kicks in when db"text" is to be shown - however, renaming the ...EN-US.lingvo file will stop it being read at all, and so it might marginally speed it up - It won't affect anything else if you are using ENglish anyway ?
Alternatively you could always edit the script itself and do a find and replace for "db">>"", but leave the def db()...end#def alone...

I think you probably need to use vanilla FollowMe or perhaps ' FollowMe and Keep' to make these rounded edges - EEbyRails is perhaps too complex for this ?

TIG · 1 Dec 2009, 22:35

@dicoy88 said:

why is it that when i try the plug in this is what i got, no success at all.

Are you using the latest version?
Have you made three Arcs or Welded the Edges into Curves?

The form you have shown works readily...SimpleEEbyR.skp

dicoy88 · 2 Dec 2009, 16:02

@tig said:

@dicoy88 said:

why is it that when i try the plug in this is what i got, no success at all.

Are you using the latest version?
Have you made three Arcs or Welded the Edges into Curves?

The form you have shown works readily...[attachment=1:3p46zpil]SimpleEEbyR.skp[/attachment:3p46zpil][attachment=0:3p46zpil]SimpleEEbyR.png[/attachment:3p46zpil]

Yes i've done it all exept that im still using the SKP6. I didnt use SKP7 yet coz my Vray is for Skp6.

TIG · 2 Dec 2009, 16:13

It should work OK with v6 and v7...
I no longer have v6 available after a HD fry-up!
Please try the thing again, but with the Ruby Console open and send us any errors that get reported - they might help pinpoint the problem and fix it...

boofredlay · 2 Dec 2009, 19:39

John, would you kindly explain the steps you are following to get that result?
Thanks.

boofredlay · 2 Dec 2009, 20:56

Thanks John. The step I was getting confused on was dividing the legs of the square (rectangle). The skp you posted came in un-welded and a bit disjointed which added to my confusion. See image. I got it now. This is a much welcomed script, thanks TIG. And thanks again John.

JClements · 2 Dec 2009, 21:11

Create circle, be conscious of the number of segments (use a multiple of 4). This one has 16 segments.
Create rectangle and divide each edge into 4 segments. Select all 16 edges and weld.
Position and rotate circle.
Add a few constuction points to define where a connecting curve would have to bend 90° (you could carefully determine specific locations, I just guesstimated), these will serve as snapping points for Steps 5 and 6.
Use the BezierSlineCurve script to draw a "Classic Bezier curve" from center of circle to a "halfway point" between it and the square. Draw a second bezier curve from that point down to the center of the square.
Explode each bezier curve. Select the resulting segments and Weld them to form a path (actually a "Profile" per the terminology of TIGs script.
Run the TIGs script. Select the select the path, the rectangle and the circle are to be regarded as "Rails" so click on each once.
Answer the script prompts. Answer "No" to the last prompt to "Erase Original Lines".
Select the square and add a face. Do the same for circle. Extrude both.

JClements · 2 Dec 2009, 21:16

TIG,

I hope people appreciate what this script is capable of.

Think of the time it would take to create something like this without it.

[EDIT] the attached .skp has been update with a welded, 16 segment square.

X.skp