Since Sketchup has its limit, i decide to rebuild my model in another different program that would give better quality then Sketchup. It is called Autodesk Alias Automotive, a specialised program in indusrty. It doesn't take me long time to finish the model in Alias.
First step is to insert picture that has been done previously into Alias.
If i want to insert a picture, i need to create a new canvas first.
I start creating a circle by using circle tool and then magnify it.
Create a circle in smaller diamter by using offset tool.
Copy these circles to the rear wheel.
Next, i draw the shoulder lines using new CV tool.
I draw another two lines to create a surface using rail surface tool.
And then project the shoulder lines i just draw onto this surface.
Connect the curve on surface and shoulder line by drawing another few CVs.
Then i use rail surface tool to create a new surface between shoulder line and curve on that surface.
Then create a new surface using rail tool and project the lower shoulder line onto it.
Trim the rest of surface.
I repeat the previous steps to build a surface to fill the gap between the two surface i create earlier.