Helmet Modding
Find your Steam ID
You can see your steam ID with this online tool
What do you need
You can use 3D Editing software like Maya/Blender/3DS Max/etc to mod your helmet.
You need an helmet 3D model and you need to scale and rotate it as the helmet model you can find in this location …Steam\steamapps\common\TrackDayR\Track Day R_Data\StreamingAssets\skins\default-skin-helmet-0 (Road type) or Steam\steamapps\common\TrackDayR\Track Day R_Data\StreamingAssets\skins\default-skin-helmet-1 (Dirt type).
You have to export the helmet in .obj format.
Where To Put Your Skins
To use your new helmet you have to create a folder named YOURSTEAMID-skin-helmet-0 (Road type) or YOURSTEAMID-skin-helmet-1 (Dirt type).
In that folder you have to put the helmet 3d model together with .mtl and .jpg (livery/visor/etc.)
The folder must to be located in …\Documents\TrackdayR\skins