3D printer resolution

[cbernhardt]

I am looking into purchasing a 3D printer and have a question concerning the resolution of the final printed model. I have a 3D model of a car that has over 1,000,000 triangles. The model is currently scaled to full size. I would like to be able to print the model out so that it would be only about 30mm in length. If I resize the model to this size, a lot of the triangle sides are smaller than 0.005 mm, which is smaller than the resolution of most 3D printers. So what happens to these triangles? Are they skipped, printed with just a dot, or what?

[Davo]

They are averaged to the resolution of the printer when sliced (converted into gcode).

[Marrrs]

You can download a free slicer with a graphic representation of the printed layers, to get an idea of how it would work out on a standard fdm printer. https://www.craftunique.com/craftware 30 mm is a really tiny car!

[cbernhardt]

OK, After a little more study I understand the function of the slicer. I downloaded the "Cura" slicer and loaded an STL file. The image below shows the result.
wheel.jpg
The first picture shows the density of the triangle mesh in the STL file. This is a very "dense" model. A lot of the triangle sides are less than 0.5mm.
The center picture shows a colorized image inside the Cura program.
The last picture shows the GCODE output in yellow which represents the printer output, with the red representing the triangle mesh. As you can see there is no output in the center of the (wheel) image. All of the surfaces in this model are represented by a single layer of triangles, so I am assuming that the reason there is no yellow in the center is because there is no inside and outside surface to fill. If this is correct, is there a way to fix this short of having to add another surface on the "inside" of each "outside" surface.

I am new to 3D printing, so I may not be using the correct nomenclature to describe what is happening, but I hope you get the picture.

Charles

[Marrrs]

If you go to the "machine" tab i Cura and change the nozzle size, you will notice that a machine with a finer nozzle would be able to produce more of the fine details in your model, but maybe not all. What you are exploring are the limits of how small details an fdm printer can achieve. Successful designing for fdm involves a great bit of understanding of the capabilities and limits. This is a favorite speech I have found on this subject: https://youtu.be/Z8ZthdEifOo It goes along with this slideshow: http://www.slideshare.net/KacieHultgren/top10-tips-for