How to see an exploded view of a STEP assembly online (free)

To see an exploded view of a STEP assembly without CAD software, drop the .step or .stp file onto MeshMarkup's free STEP viewer and click the Exploded view button on the left toolbar. Drag Spread the parts to pull the assembly apart. Pick X, Y or Z to spread it along one direction only, and choose a part under Stays still to keep it where it is while the rest move away. You don't need an account.

#Explode a STEP assembly

1. 1

   Open the free STEP viewer

   Go to /viewer/step in Chrome, Edge, Firefox or Safari. A desktop browser is best for big assemblies.

2. 2

   Drop your file

   Drag the .step or .stp file onto the box, or click it to choose the file. The assembly opens with its part names and colours. IGES (.igs, .iges) works the same way.

3. 3

   Open the Exploded view panel

   Click the Exploded view button on the toolbar down the left edge, or press E to jump straight to half exploded.

4. 4

   Spread the parts

   Drag Spread the parts from 0 to 100%. The parts move as you drag, so you can stop at any point.

5. 5

   Pick a direction

   Leave All for a quick overview, or pick X, Y or Z to spread the parts along one direction, like an exploded drawing.

6. 6

   Hold one part still

   Under Stays still, pick the base, housing or frame. Everything else moves away from it.

#All, or one direction?

All pushes every part straight out from the middle of the assembly. It's the fastest way to see what an assembly is made of, but parts travel every which way, and small parts near the middle barely move.

X, Y or Z is closer to how an exploded drawing looks. The viewer takes the parts in the order they sit along that direction and moves each layer just far enough to clear the parts in its path, plus a gap. Stacked layers end up evenly spaced, and parts at the same height, like a row of buttons, move together.

The right letter is the direction the product comes apart in. For a device housing it's usually Y, so the cover and buttons lift off the base. For a cabinet it's the direction the doors face, and for parts on a shaft it's the direction of the shaft. If the result looks odd, try another letter: it takes a second.

#Find your way round the parts

• Part names: turn on Part names on hover in the Display mode menu, then point at any part.
• Parts list: the Parts list button opens the assembly's tree. Hide a part with the eye, or show one part on its own. See hide and isolate parts.
• Section cut: to see inside without pulling it apart, use Section cut instead. See section cut and exploded view.
• Measure: the ruler measures between any two points, at the model's real size.

#When there's nothing to explode

The Exploded view button only appears when a model has more than one separate part.

• An STL, OBJ or single-body file is one piece of geometry, so there's nothing to pull apart. Export the assembly as STEP instead. See how to export STEP.
• A part with several bodies may come through as one part, depending on how your CAD program writes the STEP. Exporting it as an assembly keeps the parts separate.
• Your CAD program's own exploded view isn't read from the file. A STEP file carries the parts in their assembled positions, and MeshMarkup makes its own exploded view from those positions.

#Show the exploded view to a client

The free viewer is for you: nothing you set there is kept. To send the assembly to a client already exploded, upload it to a model in your account, set the exploded view on the model page, and send a review link. The client opens it exploded the way you left it, including the direction and the part that stays still, and can put it back together or change the view for themselves.

They can also click any part to pin a note on it, even while it's exploded, and the note stays on that part when the assembly goes back together. See send a STEP file to a client who has no CAD.