The Top Essential Thing to Know for 3D Design Modeling
Difficulty: Noob
Objective: This post is for those of you who have just started 3D Printing and Computer modeling. There are a few things that I have found absolutely essential to know and would be what I would want to know if I was just starting. Search this blog to find a more in depth post about a certain topic...
Think of the size and amount of the faces that make up the model as high definition. If you want your model to look like an 8-bit video game then use large and few faces. But if you want your model to look 1080p high def then you will need lots of faces that are small. As a rule of thumb all of your faces should look similar to each other in size and shape. The main exception is if certain areas of your model have more detail. For example if you were modeling an arm, the knuckles you need more faces than the rest of the model in order to get the detail of the wrinkles.
The sphere above for example, has bad uniform geometry. Notice how the faces near the equator are compared to those at the poles. They go from squares to rectangles to triangles. This is why I almost never start with a sphere, but rather use a cube and evolve the cube to a sphere by subdividing it.
Only subdivide the geometry when you have no other choice. Subdividing is a way that makes 1 face become 4 faces giving the model more geometry to work with and making better detail. Life would be great if you could subdivide a million times, however the computer can't process that. When you start it will be tempting to simply subdivide the model to acheive what you want. But you will run into a dead end when your computer can't handle it. Therefore if you can make good topology, then you won't need to subdivide the model as much and your computer will love you and you won't be yelling at your computer. It's very easy to go from low definition to high. To see this in action subdivide the square or Suzanne the monkey, to see how easy it is to get better definition. So don't worry if your model looks too blocky it will smooth out in a blink of an eye. Definitely learn to use the multistage tool.
Your geometry can be composed of many shapes, the best is geometry made of all squares. The reason is because squares make editing a model easy. For example you can add or deleted an edge loop like a boss. Other shapes won't. The other common way is to use triangles which is mostly used in video games because less geometry is needed speeding up the processing of the game. But for 3D printing we aren't concerned about how many faces there are, as long as we can model it. Also if you cut a square diagonally in half it becomes two triangles, so if you have to convert it, it is easy. I almost always start my model from a square and almost always only use square faces.
There is usually a tool to find non-manifolds on a model, which are problems the printer has with the model. When you design, often check the model for non manifolds. On Blender this can easily be done in edit mode--}select non-manifolds or hotkey (shift+alt+ctrl+M). A simple way to accidentally create a non-manifold is to duplicate geometry. This can be done by extruding geometry but not actual translating it to a new location. Even more so often when you undo an action make sure you undo enough times. Very often the non-manifolds I find in my models are due not pushing undo enough.
The 3D Printing Ninja
3DNinjaneer@gmail.com
Objective: This post is for those of you who have just started 3D Printing and Computer modeling. There are a few things that I have found absolutely essential to know and would be what I would want to know if I was just starting. Search this blog to find a more in depth post about a certain topic...
To learn how to use Blender see this post: Blender Curriculum: Video Tutorials
1.) Topology
When you design a model for 3D printing, (especially Blender) there a thing called topology which is the geometry that makes the model. If you are like me, at first you won't care about the topology, but eventually you will realize that good topology makes your life so much easier in the long run. Bad topology greatly limits the ability to modify the model, increases the risk of non-manifold problems, and just doesn't look pretty. Just remeber this: If you start with bad topology it's a snowball effect where one little problem becomes thousands quickly. So take your time at the beginning because good topology stays better, bad gets worse. Good topology takes practice to get into good habits while modeling. The following are some of those good habits.
Uniform Geometry
Think of the size and amount of the faces that make up the model as high definition. If you want your model to look like an 8-bit video game then use large and few faces. But if you want your model to look 1080p high def then you will need lots of faces that are small. As a rule of thumb all of your faces should look similar to each other in size and shape. The main exception is if certain areas of your model have more detail. For example if you were modeling an arm, the knuckles you need more faces than the rest of the model in order to get the detail of the wrinkles.
The sphere above for example, has bad uniform geometry. Notice how the faces near the equator are compared to those at the poles. They go from squares to rectangles to triangles. This is why I almost never start with a sphere, but rather use a cube and evolve the cube to a sphere by subdividing it.
Subdivide
Only subdivide the geometry when you have no other choice. Subdividing is a way that makes 1 face become 4 faces giving the model more geometry to work with and making better detail. Life would be great if you could subdivide a million times, however the computer can't process that. When you start it will be tempting to simply subdivide the model to acheive what you want. But you will run into a dead end when your computer can't handle it. Therefore if you can make good topology, then you won't need to subdivide the model as much and your computer will love you and you won't be yelling at your computer. It's very easy to go from low definition to high. To see this in action subdivide the square or Suzanne the monkey, to see how easy it is to get better definition. So don't worry if your model looks too blocky it will smooth out in a blink of an eye. Definitely learn to use the multistage tool.
Triangles, Squares, or Polygons?
Your geometry can be composed of many shapes, the best is geometry made of all squares. The reason is because squares make editing a model easy. For example you can add or deleted an edge loop like a boss. Other shapes won't. The other common way is to use triangles which is mostly used in video games because less geometry is needed speeding up the processing of the game. But for 3D printing we aren't concerned about how many faces there are, as long as we can model it. Also if you cut a square diagonally in half it becomes two triangles, so if you have to convert it, it is easy. I almost always start my model from a square and almost always only use square faces.
Non-manifolds
There is usually a tool to find non-manifolds on a model, which are problems the printer has with the model. When you design, often check the model for non manifolds. On Blender this can easily be done in edit mode--}select non-manifolds or hotkey (shift+alt+ctrl+M). A simple way to accidentally create a non-manifold is to duplicate geometry. This can be done by extruding geometry but not actual translating it to a new location. Even more so often when you undo an action make sure you undo enough times. Very often the non-manifolds I find in my models are due not pushing undo enough.
To learn more about non-manifolds see this post: Non-manifolds: Your Worst 3D Printing Nightmare
Overhangs
Because many 3D printers cannot print mid-air there is a limit to how steep an object can be before it will not print. If you object exceeds this limit then it will need supports. Supports can be messy, so ideally you want to orient and design your model to use no or as few supports as possible.
Please leave your comments.
and as always thanks for visiting,The 3D Printing Ninja
3DNinjaneer@gmail.com
Category: Basics, Blender, Design, G-code, Non-manifolds, Noob, Raft, Supports, Topology, Tricks & Tips
0 comments