What CADAI is
CADAI is a web tool for anyone designing a mechanical part.
You upload the part, describe how it gets pushed or pulled, and it shows you
where the part is under strain — which areas are carrying the load and which are along
for the ride.
It knows about 145 materials: aluminium and steel alloys,
titanium, plastics, 3D-printing filaments, composites and more. Nothing to install — it runs
in this browser tab.
Why you'd use it
When something pushes on a part, the force doesn't spread out evenly.
It travels along certain paths through the material, and everywhere else does comparatively little.
You usually can't tell which is which by looking at it.
CADAI works it out and draws it: busy areas red, idle areas green.
That tells you whether a part is strong enough, where it would fail first, and whether you are
carrying material that isn't earning its place.
Using it
1. Give it a part. Drag a STEP file onto the box at the top left.
(STEP is the standard export format from Onshape, SolidWorks, Fusion and the rest.)
No file handy? Click one of the example thumbnails.
2. Say how it's loaded. In the "Load context" box, write it the way
you'd say it out loud:
bolted at the left end, something presses down about 40 lb on the far end, 1/4 in 7075 plate
Press Read this & set the fields below. The boxes underneath will
change to match — that's how you know it understood. Anything it got wrong, type over.
3. Press Run. Ten to thirty seconds. The tabs along the top switch
between the strain picture and a 3D view you can spin around.
Lightening a part — optional
If your part is a flat plate, you can tick Pocketing (2D plates)
before running. CADAI will then go a step further and design cut-outs in the idle areas while
leaving the loaded ones intact. Machinists call this pocketing; done well the part comes out
noticeably lighter and just as stiff, and done by eye it's guesswork.
You get a third tab with the plan on it:
■ Green — cut this out.
■ Red — leave it, the force
travels here.
■ Grey — the ribs and outer edge
that hold it together.
Leave the box unticked and you simply get the strain picture,
which is all you need if you're checking a part rather than redesigning it. Parts that aren't flat
plates are analysed as solids and skip this step.
If a coloured bar appears at the top
Something looks off — usually a number that doesn't match the part.
The bar says which box to check. Red is worth stopping for; amber just means the answer is a bit rough.
Ask it questions
The panel on the right answers questions about CAD, machining and materials,
and shows where each answer came from. Try "how thick should a gusset be" or
"what's the difference between 6061 and 7075".
One important thing. CADAI is a sanity check, not an approval. It works from a simplified version
of your part and ignores welds, bolts, sudden impacts and metal fatigue. A green picture means the
simplified model looks fine, which is not a promise about the real part. If it carries a load
that matters, have someone qualified check it before you build it.