This is a read-only archive of the inkscapeforum.com site. You can search for info here or post new questions and comments at It is a part of a bigger project, that I would like to construct some circle arches for.
-file attached-
All the arches should be concentric, with the same radius, and with the same starting point.
Only the ending point should differ, I would like to snap them to the guide lines, but I can't get it right.
Rectangle's handles snap well, I have no idea why arch handles doesn't.
Am I doing something wrong? Is it possible to snap that?
Anyway I wanted to use the snap function here as dividing the unnecessary parts of duplicants of the original arch is less accurate.
snapping arch's end to guide line
snapping arch's end to guide line
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Re: snapping arch's end to guide line
It's more of a theoretic question, now that I went with this approximate version, and realised that the arch in itself has bigger inaccuracy than the end point coordinates have.
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Re: snapping arch's end to guide line
Hi.
Interesting find - I would report it as a bug.
RGDS
Ragnar
Interesting find - I would report it as a bug.
RGDS
Ragnar
Good Luck!
( ͡° ͜ʖ ͡°)
RGDS
Ragnar
( ͡° ͜ʖ ͡°)
RGDS
Ragnar
Re: snapping arch's end to guide line
Endpoints of arcs and sectors don't snap at least while adjusting them it's a known bug I have found a good workaround to be to use a 3 smooth node spiro path which always gives you an arc you can snap those end nodes in every way!
Your mind is what you think it is.
Re: snapping arch's end to guide line
For the construction I needed to divide each arch into equal sections.
Tried the modify extension to do that on a spiro spline, but it didn't work.
It decreased the number of nodes instead of adding new ones.
And spiro splines can produce weird stuff, like in the attached file.
Tried the modify extension to do that on a spiro spline, but it didn't work.
It decreased the number of nodes instead of adding new ones.
And spiro splines can produce weird stuff, like in the attached file.
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- bg1.svg
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Re: snapping arch's end to guide line
Moving on with the construction, other snapping problems appear:
Bounding box corner doesn't snaps to path,
while rectangle tool does by the handle.
It's not lethal, the rectangle tool can work here.
BUT the other thing would be important:
how to snap exactly to the intersection of a path and a guide line?
-see attached file-
Inkscape properly snaps to both, but to me it seems it doesn't find the intersection of them.
Is there any workaround for that?
Edit: Though to the intersection of a path and a guide line inkscape doesn't snap, the same coordinates can be achieved by using two paths and snapping to the intersection of them.
So two problems solved, two bugs to fix.
Bounding box corner doesn't snaps to path,
while rectangle tool does by the handle.
It's not lethal, the rectangle tool can work here.
BUT the other thing would be important:
how to snap exactly to the intersection of a path and a guide line?
-see attached file-
Inkscape properly snaps to both, but to me it seems it doesn't find the intersection of them.
Is there any workaround for that?
Edit: Though to the intersection of a path and a guide line inkscape doesn't snap, the same coordinates can be achieved by using two paths and snapping to the intersection of them.
So two problems solved, two bugs to fix.
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- bseg6h3.svg
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Last edited by Lazur URH on Wed May 01, 2013 7:32 am, edited 1 time in total.
Re: snapping arch's end to guide line
Didn't mean to start a new tread for some more upcoming problems, as this is for the same project:
The dynamic offset handle doesn't snap.
I want to draw paralell paths, like with the interpolate command, but for each line crossing exact points.
This made me try the dynamic offset, but it doesn't seemed to be helpful.
Is there an easy workaround for that, or its again only the old-fashioned manual way?
The dynamic offset handle doesn't snap.
I want to draw paralell paths, like with the interpolate command, but for each line crossing exact points.
This made me try the dynamic offset, but it doesn't seemed to be helpful.
Is there an easy workaround for that, or its again only the old-fashioned manual way?
Re: snapping arch's end to guide line
Which version of Inkscape are you using? Have you tried a nightly build of the upcoming v0.49 yet? It has a lot of tiny snapping improvements!
Snapping the handles of an arc while dragging them along the arc is not possible yet. Inkscape can currently only snap along straight lines, and as of recently also while rotating objects in the selector tool. Moving a handle along an arc (which could even be transformed to be an ellipse) has not been implemented.
Snapping the handles of an arc while dragging them along the arc is not possible yet. Inkscape can currently only snap along straight lines, and as of recently also while rotating objects in the selector tool. Moving a handle along an arc (which could even be transformed to be an ellipse) has not been implemented.
Re: snapping arch's end to guide line
All on Inkscape 0.48.4 r9939.
For other inaccuracy problems my workaround will be scaling all the elements up high,
and drawing aproximate results, then scaling things back down.
Not a nice solution, but still with all work being done manually, bigger errors appear.
For other inaccuracy problems my workaround will be scaling all the elements up high,
and drawing aproximate results, then scaling things back down.
Not a nice solution, but still with all work being done manually, bigger errors appear.
Re: snapping arch's end to guide line
Ouch, scaling is not a very comfortable workaround 
Some comments:
- To snap to the guide - path intersection in v0.48: first move the guide's origin along the guide (press ctrl while dragging the origin) and snap it to the path. Now you will have a node at the intersection, to which you can snap anything. In v0.49 however you can just snap to a guide-path intersection directly, provided that snapping to intersections has been enabled
- Bounding boxes only snap to other bounding boxes and to grids/guides. This is not a bug but is by design. This is because the corners of a visual bounding box (most commonly used), should not be snapped to a path, as this would align the outside of the stroke to the centerline of the stroke. For narrow strokes this would easily go unnoticed, but would lead to inaccuracies of which the user is unaware. And snapping should either be accurate, or not occur at all!
- A bug has been filed for the not-snapping of the dynamic offset handle, see launchpad https://bugs.launchpad.net/inkscape/+bug/1174858
- To trim an arc, you could consider converting it to a path and cutting it with another path (e.g. a line running from the center at the desired angle). See the Path menu -> cut path
- v0.48.4 has a nasty snapping bug, which will be fixed for v.0.48.5 (should that version see the light sometime) and v.0.49. See https://bugs.launchpad.net/inkscape/+bug/1093739/comments/10
- v0.49 will have all of this: http://wiki.inkscape.org/wiki/index.php/Release_notes/0.49. See paragraph #11 for the snapping enhancements!
Some comments:
- To snap to the guide - path intersection in v0.48: first move the guide's origin along the guide (press ctrl while dragging the origin) and snap it to the path. Now you will have a node at the intersection, to which you can snap anything. In v0.49 however you can just snap to a guide-path intersection directly, provided that snapping to intersections has been enabled
- Bounding boxes only snap to other bounding boxes and to grids/guides. This is not a bug but is by design. This is because the corners of a visual bounding box (most commonly used), should not be snapped to a path, as this would align the outside of the stroke to the centerline of the stroke. For narrow strokes this would easily go unnoticed, but would lead to inaccuracies of which the user is unaware. And snapping should either be accurate, or not occur at all!
- A bug has been filed for the not-snapping of the dynamic offset handle, see launchpad https://bugs.launchpad.net/inkscape/+bug/1174858
- To trim an arc, you could consider converting it to a path and cutting it with another path (e.g. a line running from the center at the desired angle). See the Path menu -> cut path
- v0.48.4 has a nasty snapping bug, which will be fixed for v.0.48.5 (should that version see the light sometime) and v.0.49. See https://bugs.launchpad.net/inkscape/+bug/1093739/comments/10
- v0.49 will have all of this: http://wiki.inkscape.org/wiki/index.php/Release_notes/0.49. See paragraph #11 for the snapping enhancements!
Last edited by dvlierop on Wed May 01, 2013 4:07 am, edited 1 time in total.
Re: snapping arch's end to guide line
Maybe if I pictured the whole thing right, it would me much clear:
I'm drawing sections of a "3D" model, which is made of toruses.
Originally I could create such sections by cutting only one torus, thus the workaround was easier, but the picturing of the process is not the best considering it doesn't follow other section's process.
Will upload some files shortly.
I'm drawing sections of a "3D" model, which is made of toruses.
Originally I could create such sections by cutting only one torus, thus the workaround was easier, but the picturing of the process is not the best considering it doesn't follow other section's process.
Will upload some files shortly.
Last edited by Lazur URH on Wed May 01, 2013 7:33 am, edited 1 time in total.
Re: snapping arch's end to guide line
Here is the construction of a section:
Here are all the existing sections in a pdf:
https://dl.dropbox.com/s/mcvqefyp84a0uf7/ssect1.pdf
Here are the remaining ones, with the work to be done in a svg:
https://dl.dropbox.com/s/pk0b6mxskpbfudn/ssect2.svg
The red arches should be changed to be like the yellow ones on that example image.
That means, "cutting" them to half, and adding smaller arches to them, all to fit perfectly with the resulted section drawn on he right with light blues.
Pretty much impossible even with the arch's end snapping.
If the dynamic offset could snap, it would be easier.
By the way these were drawn as paths, to mimmick a circle by 200 nodes -for future modelling in blender and such.
Here are all the existing sections in a pdf:
https://dl.dropbox.com/s/mcvqefyp84a0uf7/ssect1.pdf
Here are the remaining ones, with the work to be done in a svg:
https://dl.dropbox.com/s/pk0b6mxskpbfudn/ssect2.svg
The red arches should be changed to be like the yellow ones on that example image.
That means, "cutting" them to half, and adding smaller arches to them, all to fit perfectly with the resulted section drawn on he right with light blues.
Pretty much impossible even with the arch's end snapping.
If the dynamic offset could snap, it would be easier.
By the way these were drawn as paths, to mimmick a circle by 200 nodes -for future modelling in blender and such.
Last edited by Lazur URH on Tue Sep 03, 2013 3:19 am, edited 2 times in total.
Re: snapping arch's end to guide line
I don't understand why you are creating all these individual cross-sections manually. Can't you just create a 3D volume in Blender / SketchUp / ... and create the cross sections automatically?
Re: snapping arch's end to guide line
It is a part of an even bigger project...
I want to create a calligraphy letter in 3D with that 3D object used as a pen shape.
The main reason I'm using this workaround is, that there is no 3D solution in blender for that.
It is the only way I could figure out to work: create cross sections of the "pen shape", then,
use it to create separate sections of the letter, then put it all together in 3D.
Obviously this should be done much easier if I was into coding.
But if that ever happen, there will be more things to come.
I want to create a calligraphy letter in 3D with that 3D object used as a pen shape.
The main reason I'm using this workaround is, that there is no 3D solution in blender for that.
It is the only way I could figure out to work: create cross sections of the "pen shape", then,
use it to create separate sections of the letter, then put it all together in 3D.
Obviously this should be done much easier if I was into coding.
But if that ever happen, there will be more things to come.
Last edited by Lazur URH on Wed May 01, 2013 7:37 am, edited 3 times in total.
Re: snapping arch's end to guide line
That's tricky indeed! I only know that you can sweep any 2D profile along a path, in all 3D mechanical CAD programs. You might achieve some calligraphic like effects with these and then export to stl. Sweeping a 3D body along a path is something I've never seen before... The only program I can think of that could do that is FreeCAD, but also quite hackish: create a 3D body, create duplicates along a path at short distances, and do boolean unites on these duplicates. Unfortunately, these boolean operations in FreeCAD are quite buggy.
Re: snapping arch's end to guide line
Unlike Dvlierop I could not understand your illustrations at all. It looks like you are attempting to skin along a straight path instead of sweep along a 3D path? have you tried the array modifier to generate geometry and then render as wire at a high resolution that you can then trace in Inkscape? Maybe that is not precise enough?
Your mind is what you think it is.
Re: snapping arch's end to guide line
Here is a model of the same 3D letter with a different approach:
This one was created by fattening a model that was like created with sweeping a 2D profile along the same path.
All by editing that basic shape, but the resulted model's topology just isn't right.
On the constructing material, this 3D render may help understanding the model:
Cannot explain it any further, that is just how constructing in Monge system goes.
This one was created by fattening a model that was like created with sweeping a 2D profile along the same path.
All by editing that basic shape, but the resulted model's topology just isn't right.
On the constructing material, this 3D render may help understanding the model:
Cannot explain it any further, that is just how constructing in Monge system goes.
Last edited by Lazur URH on Tue Sep 03, 2013 3:22 am, edited 1 time in total.
Re: snapping arch's end to guide line
Tried the dynamic offset. It cannot produce enough small steps for anything that accurate.
Even in the linked dev bulid.
Is there a setting for that which I missed?
Even in the linked dev bulid.
Is there a setting for that which I missed?
Re: snapping arch's end to guide line
Off topic:
Lazur URH wrote:Cannot explain it any further, that is just how constructing in Monge system goes.
Yeah, I had to look it up
Monge: Gaspard Monge, father of descriptive geometry, which is the study of "the representation of three-dimensional objects in two dimensions" (from Wikipedia). How zen is that?!!
It's like studying how the artist knows what to draw!Wow, what a group of mathematitions we have here! Actually I could be a math whiz in another life. But in some ways, it seems like that last thing you'd expect in a forum which is predominantly about art. Or course I realize there are all sorts of applications for which Inkscape is an excellent tool. I guess geometry issues are to be expected, but I've been surprised how often I run into seriously higher math applications here
Basics - Help menu > Tutorials
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Manual - Inkscape: Guide to a Vector Drawing Program
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Inkscape for Cutting Design
Re: snapping arch's end to guide line
Sorry I was too lazy about that.
Here is a plan with dimensions:
Here is a screenshot of the 3D in action:
Here is the blend file for the above image:
https://dl.dropbox.com/s/2y072nqauxkgyuq/adisp3.blend
Couldn't find a good source on constructing sections of a torus in descriptive geometry.
Have no idea what happened last time, now the dynamic offset produced some closer results.
The xml editor was something I didn't try on it before, thank's for the tip!
But unfortunately it is acting weird.
When typed in a number value and clicked on the apply button, somehow the value changes to different numbers than the typed.
Here is a plan with dimensions:
Here is a screenshot of the 3D in action:
Here is the blend file for the above image:
https://dl.dropbox.com/s/2y072nqauxkgyuq/adisp3.blend
Couldn't find a good source on constructing sections of a torus in descriptive geometry.
Have no idea what happened last time, now the dynamic offset produced some closer results.
The xml editor was something I didn't try on it before, thank's for the tip!
But unfortunately it is acting weird.
When typed in a number value and clicked on the apply button, somehow the value changes to different numbers than the typed.
Last edited by Lazur URH on Tue Sep 03, 2013 3:25 am, edited 1 time in total.
Re: snapping arch's end to guide line
Here is another render of the object:
Here are the iso-lines of the pen object with the height data that I would work with:
https://dl.dropbox.com/s/6vibf8akp6odesc/mkk1.pdf
How to go on?
Is there an extension for moving a pen tool along a path, like in gimp?
The closest I know of is scatter.
And that would need booleans for a hull -as it is non-convex-, and rephrasing the resulted path for the modelling in bleender.
(Also an automation in blender on making faces based on iso-lines.)
Here are the iso-lines of the pen object with the height data that I would work with:
https://dl.dropbox.com/s/6vibf8akp6odesc/mkk1.pdf
How to go on?
Is there an extension for moving a pen tool along a path, like in gimp?
The closest I know of is scatter.
And that would need booleans for a hull -as it is non-convex-, and rephrasing the resulted path for the modelling in bleender.
(Also an automation in blender on making faces based on iso-lines.)
Last edited by Lazur URH on Tue Sep 03, 2013 3:43 am, edited 1 time in total.
Re: snapping arch's end to guide line
Well if none such existing, I'm trying to make one -if only I knew coding...
Created a topic on that:
http://www.inkscapeforum.com/viewtopic.php?f=34&t=14056&p=55138#p55138
When drawing this illustration for the topic, snapping didn't work as it should have:
With the right intersection point constructed, the yellow part was scaled.
But, with the snapping tool, I couldn't snap the bounding box's corner to the intersection of the paths, although those snapping functions were enabled.
Another reason I don't rely on that function.
Created a topic on that:
http://www.inkscapeforum.com/viewtopic.php?f=34&t=14056&p=55138#p55138
When drawing this illustration for the topic, snapping didn't work as it should have:
With the right intersection point constructed, the yellow part was scaled.
But, with the snapping tool, I couldn't snap the bounding box's corner to the intersection of the paths, although those snapping functions were enabled.
Another reason I don't rely on that function.