Reference Images For Beginners FreeCAD: Exercise 5.1 & 5.2

Welcome to the total beginners course to FreeCAD 0.20. In this is a two part lesson we will practice our tracing skill in the form of a mini project. Using the below reference photos we will create a more complex part which will consist of repeating features. We will utilise the symmetry tools to ease construction in both FreeCAD sketcher and Part Design workbench.

This project work will help teach the fundamentals of freeCAD allowing a understanding of the basics but delivering this information via teaching you different workflows.

In this tutorial we will be tracing photos imported into FreeCAD via the image workbench

https://wiki.freecadweb.org/Image_Workbench

The story of this tutorial

The idea and first attempt at creating this tutorial was back in FreeCAD 0.18.  The physical part itself, well, I have no idea what really it is, it looks like something from some flat pack furniture (I believe it was left over from a kitchen fit that was done) and it ended up in my in-tray for some months.  The first attempts at creating the tutorial didn't got well.  I first managed to record the whole tutorial without sound,  then I had a computer crash and lost the second recording as it wasn't stream to disk, followed by me losing the part which lead to me giving up on the tutorial until it re-appeared many months after.  At the time freeCAD had moved on to 0.19 and I started again only to have my laptop die and videos being corrupted.  Determination only lead to the tutorial finally being completed and released.

Tips when capturing reference images

It's import to be mindful of how you capture your images.  Quality, composition, lighting, etc will all be a factor when it comes to the stage importing and tracing.  Here are some tips to save you time and frustrations:

- Make sure you have a known scale.  Either you know the exact size of part of the subject or there is something in the image you can use.  Remember perspective will reduce this scale if the subject has depth.  You will need this scale so it can be defined in freeCAD.

– To get a decent profile of the subject the camera needs to be parallel to the object. Use a tripod, stand and / or take a photo standing from afar but zoom into the subject with the lens.  The errors in perspective reduces the further you are away.

- Take photos from the individual planes; top, right, front along with the opposites; bottom, left, back.  

- Take additional photos from as many angles as possible, zooming in on detailed parts.  You want to capture as much information as possible otherwise you may get stuck modelling a feature.

– Use a contrasting background when taking photos of your subject.

– Make sure you capture images in a lossless high-resolution format, you can always reduce the detail later but you can't increase it.  By that time the subject may no longer be available.

- Take a high resolution video, moving around the object, up and over and again zooming into the detailed parts.  This can help you to visualise certain features. The individual frames serve as additional reference images and can be extracted from the original video and loaded into FreeCAD if needs be. 

– It is harder to find the edges of your subject when there are excessive shadows or some of the object is in shade.  So make sure you have adequate lighting and it is positioned in a way to reduce shadowing.

- If possible use a flat-bed scanner.

- Resize the image down afterwards to take the load off the CAD program before using the image workbench so refine the scale from a reference . 

Reference Images and Video

The reference images are for the following video exercises hosted on my Youtube channel:

FreeCAD 0.20 For Beginners | 5.1 | Tracing from Photos Project | Repeating Features | Polar Patterns
https://youtu.be/ZgGIULSFlw0

FreeCAD 0.20 For Beginners | 5.2 | Tracing from Photos Project | Finishing Our Model
https://youtu.be/WZZK4vmXK9Q

Some of the images are taken in not the best composition and quality.  This has been done on purpose to help you understand the challenges that may occur when tracing such subjects.

Please note:  To download right click and save as on each of the images.

Note: Above the scale has been included but it will be useless on it's own as it's not.  Below the scaling will allow for the bottom of the object to be placed into scale.