Geometry modification of Perrinn myP1

Perrinn myP1 is an open-source LMP1 (LMP = Le Man Prototype) racing car.

Its 3D data is published on their website (http://perrinn.com/myp1) in both STL and STP format.

I'd like to perform a CFD simulation on it, but there were some problems.

Badly defined surface

Parting lines

(These are not errors, but useless for CFD)

Therefore I modified the STP file on Rhino5, and export the modified body as an STL file to create a watertight and smooth surface mesh.

To fix them, I remade original surfaces using Untrim command, and re-trimed them with proper boundaries.

Untrimmed surfaces

Extract proper boundaries

Re-trimmed surface

I repeated this modification all over the car, the result is as shown below. But front brake ducts could not be joined with surrounding surfaces.

Original STP file

Modified geometry

Open edges colored in magenta

I exported this as an STL file. When checking the STL file on netfabb, some more errors were found on several surfaces as well as on the front brake ducts.

STL repair mode of netfabb Basic

The problems were easily solved by its "Automatic repair" feature. 

Additionally, I separated 4 individual tyres from the bodywork in order to make tyres rotation possible.

STL after repaired

(Tyres are separated from the bodywork)

This STL file is watertight (there is no isolated edge to be stitched), so it can be used by foamyHexMesh as well as snappyHexMesh.

(Postscript added on 19/10/2014)

The STL file(s) presented in this article can be downloaded here.