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arch2b
2012.07.12, 08:05 AM
have you tried some of the new automated methods for generating models such as iOS apps (http://itunes.apple.com/us/app/123d-catch/id513913018?ls=1&mt=8)?

seems like an easy way to get a car model generated for further manipulation depending on how the model can be configured. not sure it does much good if it creates a solid form.

Fovea3d
2012.07.12, 09:48 AM
have you tried some of the new automated methods for generating models such as iOS apps (http://itunes.apple.com/us/app/123d-catch/id513913018?ls=1&mt=8)?

seems like an easy way to get a car model generated for further manipulation depending on how the model can be configured. not sure it does much good if it creates a solid form.

I tried the ancestor of this app called Photomodeler.

In fact acquiring the gross shape of a car is not the biggest part of the job.
Modeling the shape can be done from an existing 3d model of a car, from side/front/top pictures, or from a 3d scan just like the 123 app would produce.

There is still a long process by hand to optimize the mesh so it will be suitable for print.
For instance with a 3d scan you will end up with a dense (http://www.nanospeeders.com/photos/shapeways/modeling.jpg) and intricate mesh that can render good for pictures, but it will take sometimes hours to reduce errors and make the 3d scan "clean" for print.
It is just like "calking" the source model with simplier lines to make a cleaner one that is easier to work with.
But there is also a second shell to model, which is the "inner" surface of the body, this is where the thickness of the body is determined, its flexibility, the amount of material it will use for print and so the final price, etc.

What is good when working with cars is that only one half of the car needs to be modeled and then a symetry is applied.

leonabi76
2012.07.12, 10:31 AM
Like I mentioned on another thread, Fovea, you've inspired me to pick up and dust off my skills. Do you use Accutrans to check for watertight meshes? @Arch2b, as for iOS, the only real app for creating good mesh models is VertoStudio 3D (http://itunes.apple.com/us/app/verto-studio-3d/id417187334?mt=8). This actually allows for one to make good mesh models.

However, as Fovea has pointed out, getting the basic geometry (cubes, cylinders, spheres, etc.) to do what you want is not that easy! As with many things picking it up has a short learning curve, but its an art and takes several years to master. Unless you're a savaunte! Haha!

I use Trimble's SketchUp (http://sketchup.google.com/) to do my models. It's not an iOS app but it is probably one of the easiest to pickup of all the software out there. It doesn't have as many bells and whistles as say Maya or 3DS Max, particularly on the export side. But SketchUp has some good beginner tutorials to get you going.

Fovea3d
2012.07.12, 04:46 PM
Like I mentioned on another thread, Fovea, you've inspired me to pick up and dust off my skills. Do you use Accutrans to check for watertight meshes?

I use what Shapeways recommends, Netfabb (http://www.shapeways.com/tutorials/how_to_use_meshlab_and_netfabb)

This is also what they use to accept/reject a model.

Their interest is that a model is the thickest/using the most amount of material while I prefer having a shell light, thin and cheap. It ends up with such conflicts where they ask me to make a section thicker, hence increasing the overall price for the print. They even recently changed the rule of "0.7mm minimum thickness" to "0.7mm but increased thickness for models longer than 120 mm"... ;)

This is what they sent me, saying the body is not thick enough for its length... Arch2b will tell you thats not true ;)

http://www.nanospeeders.com/photos/shapeways/cudathick.jpg

I protested saying it printed OK the first time and sent them the pic of the painted green one, now cross fingers they wont reject it in the future.

Keep in mind that when the model is 0.7 mm thick, it will cost the double with 1.4 mm thickness.