Can You Upload Your Own CAD to an Online CFD Tool?

September 2026

Yes. You do not need to install heavy software to test your own design anymore. With CFD Tunnel you can upload your own 3D model right in the browser and run a real simulation on it. This guide covers which file formats work, how to get a clean result, and what to do if a model does not solve well.

Which file formats work

CFD Tunnel accepts the two formats almost every CAD program can already export.

.stl, which is the most common format for 3D models and 3D printing.
.obj, which most CAD and 3D tools can export just as easily.

If your design lives in something like Fusion 360, SolidWorks, Onshape, or Blender, you just export it as one of these and you are ready to go. You do not need to convert it to anything special.

How to upload and solve

On a Premium plan, open the app and look under Input Geometry in the sidebar.
Click the Upload CAD file button and pick your .stl or .obj file.
Set your wind speed, and if it is a ground vehicle, turn on the ground plane.
Press Compute 3D Flow Field and wait for the result.

Free accounts use the built-in shapes instead of uploads, so to test your own model you will need a Premium plan.

Getting a clean solve

CFD works best on a model that is watertight, which means it is a closed, solid surface with no holes or gaps. A messy mesh is the most common reason a solve looks wrong. A few simple habits help a lot.

Export a closed, single solid rather than loose surfaces.
Keep the detail reasonable. You do not need every tiny bolt and logo, and removing them makes the solve faster.
Make sure the model is oriented the way it really faces the wind, so the drag direction is right.

If a result looks strange, a broken or open mesh is usually the reason, and re-exporting a clean closed version fixes it.

What you get back

Once it solves, you see the air moving around your actual design in 3D, plus the numbers that matter. You get the drag coefficient, the drag and lift forces, and a full view of the flow. You can compare two versions of your design at the same wind speed and just look at which one makes less drag, which is the whole point of testing your own CAD instead of a generic shape.

So yes, you can absolutely bring your own design. Export it as an .stl or .obj, upload it, and you have a real simulation of your own part in a couple of minutes. No install, no workstation, just your model and the flow around it.