You should be very grateful that God made all of creation rather than some kind of mythical chance-driven process. Your doctor should be grateful! Because automobiles are designed, mechanics can fix them with manuals or (now) online programs with all the repair and maintenance information for every single model of automobile that is manufactured. Because God designed organisms, doctors and veterinarians can be trained with books and curriculum with the design features of bodies and they can have online programs to help them diagnose problems from symptoms. If chance is the creator of organisms, then logically every single person will be different in macro ways rather than micro ways. My fingerprints are different from yours, but my basic design is just like yours from egg to eighty-eighth birthday!
First, let me show you a YouTube video that will give you an idea of how mankind is developing design processes via IT technology upgrades:
It used to be that designers would keep designs in their heads as they made things. No idea who invented the first design on paper, but certainly Leonardo da Vinci would make drawings of his inventions in a manner similar to blueprints. In order to prevent people from stealing his ideas, he would deliberately make mistakes in the design so if someone got a copy and tried to make it, it would not work. Later the classic blueprint was invented. Many years after actual blueprints were replaced by whiteprints and other similar styles. When I came into the auto industry, drawings on big sheets, rolled up and transported in tubes were the standard method of sharing designs around the industry. But more modern ways of designing and sharing designs had been invented and soon the auto industry began to convert to digital rather than paper designing and sharing.
AutoCAD was the first such program I encountered. Wikipedia is actually worth using when dealing with something like this, so here is how they describe the program:
AutoCAD uses their own fork of the ACIS geometry modelling kernel."
Our company would fight over 1/4 of a penny per part to get a profit and sometimes we took a loss on some parts if the manufacturer would purchase some parts only we could make and we would get our profit on those. Being the only company in the world with one process to make an insulator no one else could make made us grow like weeds in the 80's and early 90's until some other company reverse-engineered or perhaps got a spy into the company and we had a competitor for that one. That company decided to get rid of all the senior employees and staff, then went out of business and the building burned down when they tried to remove the equipment with cutting torches (what dolts!) so it is gonzo now. But I digress...
I had a buddy in college who had a Mercury Cougar that required the motor mounts to be disconnected and the motor lifted up so the mechanic could get to one of the spark plugs!!! In fact, there are many such stories of bad design like the following:
"The identical badge-engineed Buick Skyhawk, Chevy Monza, Pontiac Sunbird, and Olds Starfire of the '75-'80 model years were equipped with a 3.8 liter V-6 that was very large for the size of the engine compartment on these small cars. The result was that, in order to change the spark plugs on the right bank of the engine, you had to disconnect the motor mounts, attach a chain hoist, and lift the engine at least a few inches in order to be able to access those plugs." from Cartalk.
Why does this happen? Well, automobile manufacturers have any number of kinds of automobiles and the cheaper models are the ones they scrimp on the most. The idea is to get the car to the dealer and sold to the customer. If someone owns a Sunbird and never lets the gas tank get down near empty, the fuel pump might not ever fail and it will be the engine or the transmission and then it goes to the junk yard, never revealing the ridiculous design decision.
But that is a problem created by management. Automobile engineers would always prefer to make good cars. Some manufacturers like Subaru make consistently reliable and well-designed vehicles in part because they allow their engineers to have more say in final designs and their plants are big on quality processes and continual improvement. Even the El Cheapo cars have to meet certain standards, though. The vehicle has to be designed to take the stresses of turns, stops, accelerations and so on of normal driving. So engineers have to take a lot of things into consideration.
When designing things, it always helps if a part is interchangeable with another part. For instance, if the four wheels of a car were all different, it would cost more to make the car. So for the wheels to be interchangeable is beneficial. If the lamps that light the brake lights also can act as running lights in another vehicle, the cost of purchasing them is less because you can purchase in more quantity. So therefore you can understand why automobile manufacturers would design several models of cars that would all be built on one frame. The GM C-Body car was the base frame for several cars. The Chrysler K-Body cars (generally some of the crummiest cars on the road) were made in the multiple millions. The Ford Taurus and the Mercury Sable were basically the same car with almost all the components being identical. C-Body GM cars were Cadillacs, Buicks and Oldsmobiles. But my factory also made the same parts for B-Body for Chevrolet as well and they were so similar we simply called them all C-Body. We made many Taurus parts and a good percentage would go into Sables but our company didn't care, they were the same parts.
When engineers get together, they talk about things like "Moment Arm" and "Load Path" while non-engineers just sit there quite left behind.
From MIT - "The Moment of a force is a measure of its tendency to cause a body to rotate about a specific point or axis. This is different from the tendency for a body to move, or translate, in the direction of the force. In order for a moment to develop, the force must act upon the body in such a manner that the body would begin to twist. This occurs every time a force is applied so that it does not pass through the centroid of the body. A moment is due to a force not having an equal and opposite force directly along it's line of action."
Making sure whatever you construct has a load path that will withstand the forces that may be exerted on it is necessary in design. Here is an illustration from an explanation of the continuous load path as applied to buildings.
From ABAG - "Load path is a chain
- It is only as strong as its weakest link.
- The figure shows a complete load path
- The roof and floor diaphragms and shear walls are links in the chain.
- The connections between the roof, walls, floors and foundation are additional links.
- These additional links serve as the connective points that complete the chain.
- The connections are just as important as the diaphragms and shear walls.
- The seismic loads imparted on a building must successfully pass through all of these elements in order to reach the ground and effectively resist an earthquake’s damaging forces.
- In other words, the load path or chain must be continuous and complete. There can be no weak links in the load path chain."