Inkscape and Prosthetics

[Melodicpinpon]

Hello,

I finished my studies and my thesis was well receiced.
I went on studying Blender and started with Inkscape, it appears that my computer lacks power to ensure a perfect 3D model out of my technique.
Still I know how to do it and will try and multiply the designs.

I learned how to do escher's tesselations for exemple.

Glad to have had your help on the first designs.

I hope you are doing fine,
Many thanks from Brussels

[brynn]

I'm always happy to try to help.

I hope you eventually find success 

[Melodicpinpon]

Hi Brynn,

I finally finished my first 3D printable orthesis using your design.
Here you have a picture of it.

Thank you!

[brynn]

Oh wow, look at that!!

Nice work 

Did you give up on the mandala design?

[Melodicpinpon]

Sorry for the late answer.
I had given up but want to go back into this.
Therefore I would like to ask you if you know how I can offset a line(I made it with the brush).
In this case, I would like to reproduce this pattern and use the same line to duplicate it.
Thank you!

[brynn]

Welcome back 

Hhmm, Inkscape doesn't have a brush tool.  If you look at the smileys when you use the full message editor (click Reply, instead of using Quick Reply)  you can click the icon of the tool that you used.  Then we will know which one you used.

I don't understand what you mean by "I would like to reproduce this pattern and use the same line to duplicate it."  Do you mean that you want to draw one line, then duplicate and offset?  And then repeat a couple more times?

Reproducing that pattern in Inkscape will not look the same.  When I look closely at those lines, they are thinner in some places and thicker in others.  when you do it with Inkscape, there won't be any kind of variation.  Of course, there is a way to create variations like that.  But it would be meticulous and detailed work.

Anyway Path menu > Inset, or Outset, or Dynamic Offset, or Linked Offset.  I would suggest using Linked Offset because it's kind of like a clone.  You will be able to adjust the parent, and all the Linked Offsets will be adjusted at the same time.

And if this will be used for the same thing as earlier in this topic, after you get all the paths how you want them, you'll need to use Path menu > Stroke to Path.  And like I did for the other design, you'll need to do a LOT of node editing, to make it all one single path, all closed and cleaned up (as I explained before).

Also as before, I'd be glad to do that work, if it would be helpful.

[Melodicpinpon]

Thank you, Brynn for the fast answer.
I will present the techniques used to do the design integration within Blender on saturday.
Some members have had a formation in Inkscape.
In Blender and as in inkscape, there is A LOT of work to get a closed shape (I did this one directly within Blender)
I tried the offset on the  but it did not leave any empty space between the original and the offset line.

You are very welcome to do this job, especially if you give me a tip or two on the way to achieve it 

Nice to speak to you again!

[brynn]

Well actually, I volunteered myself a little too soon.  I'm having a problem with my usual mouse lately, and waiting very impatiently for support from the driver manufacturer.  If they can't fix it soon, I'll have to learn to use a different kind of mouse, and that could take a while.

But, whenever I can start, you've showed 2 different images.  Which one would you want a clean SVG file for?  Also, does it need to be specifically, exactly like the image shown?  Or can something similar work?

Typically we don't see path offsets used with the Calligraphy tool.  But there's really no reason not to.  I can't say for sure without seeing the SVG file, but I'm guessing it didn't leave an empty space because the Calliraphy tool draws a closed path with a fill (black by default).  If you remove the fill, and add a stroke, if there's not one already, you'll see the offset better.

Although the offset might be different than you expect.  Try it and you'll see.

But I would use the Pen/Bezier tool  , instead of Calligraphy.  Or maybe Pencil/Freehand tool  .  If you want it to be as close to the first image as possible....  You know, I'd probably at least try Trace Bitmap.  That might be a short route to a finished product.  It will create a single closed path automatically.  Sometimes TB injects some odd distortions and extra nodes.  But it would be worth a try anyway.

I'll grab your image and give it a try.  TB doesn't need the mouse much.  Although fixing the extra nodes and odd distortions does.

Otherwise, I'd trace using Pen/Bezier tool.  Or if it only needs to be similar to that design, I might experiment with different loopy ribbon/offset designs.  I do remember that you need a certain "positive to negative" ratio, to help the material hold together well.  I was a little surprised with that design, because it has some fairly narrow areas of positive space.  We could still make them thicker, like before, if necessary.

To draw that or a similar image from scratch, there are a couple of different ways to approach it.  You could draw a single path, then use Linked offset duplicates, as you were thinking.  But there's another possible way to do it, using something called Pattern Along Path.  You'd create a short section of the ribbon pattern.  Then when you draw the paths, you don't have to duplicate and offset.  You just apply the pattern to the path.  http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Paths-LivePathEffects-PatternAlongPath.html

[Melodicpinpon]

OK, I will try that for sure soon,
Today I prepare as much as possible for the workshop,
I'll tell you how it went.

The idea to do a classic draw with pixels and then transform it into a .svg sounds good.
I achieve to merge letters together automatically within Blender; it passes through the extrusion and boolean fusion of the several letters,
which can be afterwards edited to flatten it again and so on.

There is still a loss of accuracy when I do a retopology.

The attached picture is the kind of topology that I can achieve working directly within Blender.

[brynn]

Hah!  That looks like a lace doily 

I haven't had a chance to try your first design with Trace Bitmap yet, but probably later today I can.

[Melodicpinpon]

Here are some other images that could be used.
I will scan my own and make new ones later.
Finding the best technique to create a usable mesh is the real challenge.

The second one (B&W6) is interesting:
the repetition of radiate triangles is the what I need for mandalas that cover a wide surface; is this only a tiling with radiate and then other offset tiling? (I did not achieve it yet) ...

[brynn]

Oh, those are very nice!  I've started working on another project where those designs would work very well!  http://forum.inkscapecommunity.com/index.php?topic=306.0  I already have several designs, nearly complete.  But my mouse driver is having problems, and I'm having to use the mouse that's built in to the laptop, which is not nearly as nice as my external touchpad.  So I haven't been able to do any Inkscape work lately.

Maybe some of my coloring pages would work for this prosthetics project as well?  I'll upload some, as soon as I'm able to finish them.

[Melodicpinpon]

OK, thank you, I got some better understanding of the shortest way to pass from an image to a usable mesh:

INKSCAPE

-Object To Path (Ctrl + SHift + C)


BLENDER

-3D (Object Mode) > Add > Text
-Alt + C
-Modifier : Decimate (Planar) > Apply
-3D (Edit Mode) > Triangulate (Ctrl + T)
-Modifier : Solidify > Apply
-Modifier : Remesh (Remove Disconnected Pieces: unactive+ Change Octree Depth) > Apply
-Get rid of the thickness

[brynn]

OK, thank you, I got some better understanding of the shortest way to pass from an image to a usable mesh:

INKSCAPE

-Object To Path (Ctrl + SHift + C)

If you made the drawing using Shape tools (Rectangle, Ellipse, Star, or Spiral), then Path menu > Object to Path will convert them to paths.  But it will not convert JPG or any other raster image to path or vector.

So if these are your steps for converting a JPG, then Path menu > Object to Path is a wasted step.  It will not affect the JPG at all.

[Melodicpinpon]

Hi there!

I nearly achieved a new design and a part of the method is better (making the borders).
I could work faster and cleaner (just work at all in fact) if I could merge two shapes and convert it into a single path.
Here is my problem:
Ctrl+G groups the objects and Ctrl+Shift+C converts each object into a path
but they stay separated.

Do you know how I could proceed?

[Lazur]

Hi.

Select all objects and add them together (Ctrl++).

[Melodicpinpon]

Great, it works just fine!
Of course I still have some issues with automatic functions to remesh it inside Blender,
I secretely wish I could try the Zbrush remeshers but... now that I think of it, Meshlab has plenty of different remeshers

[Lazur]

Have you tried the remesh or the late retopo modifiers?
I never used those but they seem doing a good job.

[Melodicpinpon]

Ok I got it:
My Blender is set up for 3Dprinting in order to work in millimeters and all the importations are reduced 1000 times.
I just needed to scale the mesh, apply the scale and now the Remesh modifiers achieves easily the job.
sorry for that

I can now easily get an svg file from any black and white image, and can also tile it, in order to get an svg from the whole(make sure to cut the link between the clones and the original=Shift+Alt+D),
but there is still this same error appearing inside Blender as the other time; I do not undestand where it comes from.

[Lazur]

In inkscape that look is usually a rendering issue of a too intricate path. After a few thousand nodes computing the fill rule is a bit too much I guess. Like, if you convert a text to a path each character is separated and grouped together, giving a much reliable rendering than when the characters are combined.

Similarily in blender curved paths are represented by alot of small segments, maybe it's too much to handle at once.
As a "brute force" solution I would try breaking the path apart before saving as svg,
then in blender, convert each curve to mesh, then join the inner parts together, move them up a bit in z direction and
use knife project to add those as holes to the mesh -previously outer subpath.

[brynn]

Sometimes Union isn't the right technique (Ctrl + +).  Sometimes you might need to use Combine instead (Ctrl + K).

There is Never going to be an easy way to achieve a nice clean file, without extra nodes and disconnected nodes.  That will always be the harderst part, at least in the Inskcape side of things.

I just finally got my mouse issue straightened out, so I can do that now.  If you have some design you'ver created, and you just need it all cleaned up, I'll be glad to do that.  But I really hesitate to clean up any design, until I'm sure that you're planning to use it -- because it's a LOT of work.

If it's going to be a repeated pattern, if you start with a very clean pattern unit, that will help.  But there's still the matter of connecting the paths of the  units.

Regarding screenshot 50, is that diamond shaped gap between the pattern unit not too big?  It seems like it would be very weak in that area -- prone to bulging.

I made the attached design the other day....well it's been a few weeks ago, for the coloring book project I told you about.  It's not cleaned up yet.  And of course the squares and diamonds need to be filled in.  I know it's not the pretty flowing type of design you like.  But just to show you.

[Melodicpinpon]

Actually after a few tries, I can easily get my stl from an svg from any image, I started three of the four exemples one hour ago, and the difficult part is to clean the copyright kind of blurry text.
Only with the treshold I could also use a crapy image and get a clean svg.
i spent the weekend trying to remesh this kind of stl and this is more tricky because either it destroys the shape, either it gets really heavy, and in between it leaves some errors.
The purpose of remeshing is only to get a soft mesh that can easily adapt itself when shrinked on another mesh, and actually there is no need to have such a perfect grid as can be achieved with a remesh.
Therefore I will only make some cuts in the cery long triangles and it will do.

Thank you Lazur, the Knife project was on my list and I tried but is result being a much heavier operation than a shrinkwrap.
The error in filling the plain and empties can be resolved through redoing the vectorisation with a slightly different offset, no need to try and clean it up manually.

As for the output of this work: I have to make a cover for the magazine of the professional union of the belgian orthopedists (UPBTO), I already made four, and the topic this semester is the digitalisation...If you feel like proposing something, I'd be glad to have a nice original design as the one used the other time but there should not be this lot of repair, getting a fast and clean way to work is the only way to get this method to the public some day.

Have a nice day. I leave the 30 of this month to start working in an 'atelier' in Guadalupe, no 3D on the menu but hopefully much practice 

I tried a solution to use any image, even if it is not a plain black and white; it is called TVB DESIGN and convert the picture into a buch of holes, it exports an svg(it is meant for a laser cutter), I just need to import the svg in inkscape, and merge all the curves in a single file to be able to make a mesh from it; (Ctrl ++) creates a full black square and (CtrlK) makes these empty circles... I guess I can get the result throug only using the picture and 'vectoriser le bitmap' as usual.

[Melodicpinpon]

Hello Brynn, Lazur and the others!

How are you doing?

Good news: I'm working as prosthetist in Guadalupe since may and restart designing orthopedical parts; the method I use is working well, and one of the latest has been printed by a friend in Belgium(see picture in attachment).
I wanted to try other options, and started making designs with text. It works but I have some difficulties trying to have all the letters attached (I can control the space between letters and lines but still).

I was wondering if in Inkscape or any other program, there was an option to create a non rectangular zone within which the text would enter.
I put the border of the ortosis before the 3D step, it helps a lot, but the design is distorted because of the variation of sizes of the limb.
I would like to avoid that making an image that anticipe the difference of diameter between the hand and the forearm especially, but if it is to add text, I would rather have if directly fitting this special shape than have to tweak it manually.

Thank you a lot for your help,

Gauthier

[Melodicpinpon]

Hello dears,

do you know why Inkscape does have this limit in the number of nodes that it can create without mixing the filled and empties parts?
Is there any chance to raize this number?

[brynn]

Hi Gauthier,
Congratulations!  I know this has been a lot of hard work, and I'm happy to see you succeed.

I'm not clearly understanding your questions.  You can put text in any kind of shape.  For example,

1 -- draw a circle
2 -- type some long string of text
3 -- select both
4 -- Text menu > Flow into frame

(Note that if your text is too large, or the circle too small, it won't work.)

An example in the manual:  http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Text-Flow.html

do you know why Inkscape does have this limit in the number of nodes that it can create without mixing the filled and empties parts?
Is there any chance to raize this number?

I don't understand that question.  Is this the same question you had last time, where sometimes spaces will be empty and sometimes they are filled, depending on how the nodes are arranged?

If it's the same question as before, this will always be the part of your process which takes the longest.  The only way to do it, is to look at almost each and every node, to make sure they are joined together in the right places, and there aren't any leftover end nodes.  I think with very careful planning,  you can minimize the problem.  But I don't know of any fool-proof solution.

If this is the same question, it's not about the number of nodes.  It's about whether they are joined together properly.  For this kind of project, you need unbroken paths.  However, there's no way to create the kind of design you need, and automatically have unbroken paths.  It's just "the nature of the beast".  I suppose it could be seen as a bug in Inkscape.  Perhaps Inkscape could be built with better precision, but I just don't know much about programming.

Have you ever tried any CAD programs, to make these prosthesis designs?  I have the impression that CAD offers better precision, but I don't really know for sure.  I assume there must be an open source CAD program out there somewhere.

Hhmmm.....I wonder.....  I just gave myself an idea.  I'll test before I share it