a question
How do I create 3d model from this sketch, similar to the attached model
I do not need paper birds but 3d model (stl, obj). Model I can print in 3d printer
thats easy scan it and convert it in blender. you can import the scan as height map( greyscale for more heights or b&w for just the form raised) on a standard plaine or box, then just cut off the bottom part just make sure there are enough vertexes on the object thats being raised! then export as .obj btw blender 3d is free opensourse.
trying now, cheers
you can also use inkscape to vectorize and use https://www.thingiverse.com/thing:25036 to extrude this in open scad. Or use freecad to scetch and extrude
I’m a big fan of the OpenSCAD/Inkscape method, as it works well and is relatively simple to implement.
Even though I’m not a big TinkerCAD user, nor a fan, it will also allow flat images to be imported and extruded.
I appreciate the power and flexibility of Blender, but would never suggest that program for a simpler solution called for by this model request. The learning curve on Blender is a killer.
If you use Inkscape/OpenSCAD, you may not want to use the trace option within Inkscape, as it will take the raster image and toss in a few curves where you probably want straight lines.
As a test, I screen capped the small image and converted it to vector with Vector Magic. Not such a good result for the reason noted above.
Importing the raster image and manually creating the lines in Inkscape produced much better looking birds.
If you go that route, consider the final size you desire and set the overall shape to that figure. Be sure to turn on the aspect ratio lock. Once you have the size, consider the wall thickness you desire and use Fill (none) and Stroke to set the stroke width to represent the wall thickness.
Use Path, Object to Path, then Stroke to Path to create a proper object for the OpenSCAD extension.
If you learn by experimenting, as I do, consider also to copy each satisfactory state of your work to a different layer. I did the stroke to path after setting the stroke width, but wanted to make it larger a few moments later and had no practical fall-back. Control-Z works well sometimes, but I had performed a few additional actions I didn’t want to undo to get back to the stroke-to-path option. For this particular exercise, it is easy enough to recreate the strokes for each bird, but I won’t make that mistake twice!
@Fred_U i would import that image in inkscape und use the fill tool (paintbucket) to generate the polygone
That was a fun project. 3 mm walls, 3 mm thick, 75 mm wide, height proportional. I probably won’t print them, but the exercise might stay in mind long enough for future projects of a similar form.
@Fred_U You are a genius! We are all thinking models an stuff and here you go and literally give the poster exactly what they asked for. Hats off to you!
I also love 3mm walls. Three passes with my 1.0mm nozzle and abs or petg parts are crazy strong! Froze some in liquid nitrogen so I could shatter them. Couldn’t see layer lines internally, they looked injection molded.
Use 3D Doodle
@Dianne_Fontayne perfect, that is what I was looking for
I’d completely forgotten about Doodle 3D, even though I’m one of the backers. That’s just about the simplest method available, if freehand images are acceptable.
I too am a backer 
It can be anything a pic or free hand, it’s a great piece of software to play around with.
Or like this: https://youtu.be/7Yx3HD4LDZc
Or like this: https://youtu.be/7Yx3HD4LDZc
@Martin_Jorgensen Yikes! Fifteen minutes of YouTube for Fusion 360 is serious stuff. Even though I’m not a big Tinkercad fan nor a big Tinkercad user, here’s six minutes of the same thing in Tinkercad:
Even shorter, for Doodle3D, at one minute, in German, but the language doesn’t matter:
As the OP has noted he’s going to use Doodle3D, the last video above seems more appropriate.
Scan as a bit map>open in inkscape>trace it there> save as SVG>import into Blender> scale up and convert to mesh (forgot exactly how to, it’s under one of the menus in object mode)> edit and extruded however tall you need it