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Rounded Prism Fixes

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Richard Milewski 2024-02-01 16:06:16 -08:00
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143
tutorials/Rounding the Cube.md
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@ -10,7 +10,7 @@ There are four different 3d shape primitives that you can use to make cube-like
* [**prismoid()**](https://github.com/BelfrySCAD/BOSL2/wiki/shapes3d.scad#functionmodule-prismoid) - Creates a rectangular prismoid shape with optional roundovers and chamfering.
* [**rounded_prism()**](https://github.com/BelfrySCAD/BOSL2/wiki/shapes3d.scad#functionmodule-prismoid) - Makes a rounded 3d object by connecting two polygons with the same vertex count. Rounded_prism supports continuous curvature rounding. (See [Types of Roundovers](https://github.com/BelfrySCAD/BOSL2/wiki/rounding.scad#section-types-of-roundovers)).
* [**rounded_prism()**](https://github.com/BelfrySCAD/BOSL2/wiki/rounding.scad#functionmodule-rounded_prism) - Makes a rounded 3d object by connecting two polygons with the same vertex count. Rounded_prism supports continuous curvature rounding. (See [Types of Roundovers](https://github.com/BelfrySCAD/BOSL2/wiki/rounding.scad#section-types-of-roundovers)).
BOSL2 provides two different methods for rounding the edges of these cube-like primitives.
@ -19,6 +19,16 @@ BOSL2 provides two different methods for rounding the edges of these cube-like p
* **Masking** - BOSL2 includes a number of options for masking the edges and corners of objects. Masking can accomplish rounding tasks that are not possible with the built-in rounding arguments. For example with masking you can have a cube with a different rounding radius on the top edges than the rounding radius on the bottom edges.
Cube-like objects have six named faces: **LEFT, RIGHT, TOP, BOT, FWD, BACK**.
![](https://github.com/BelfrySCAD/BOSL2/wiki/images/attachments/subsection-specifying-edges_fig2.png)
Each of those face names is a vector pointing to the face. e.g. UP is [0,0,1], and FWD is [0,-1,0]. By adding two of those vectors we can specify an edge. For example, TOP + RIGHT is the same as [0,0,1] + [0,1,0] = [0,1,1].
![](https://github.com/BelfrySCAD/BOSL2/wiki/images/attachments/subsection-specifying-edges_fig1.png)
See [Specifying Edges](https://github.com/BelfrySCAD/BOSL2/wiki/attachments.scad#subsection-specifying-edges) for more details.
## Cuboid Rounding
@ -29,12 +39,15 @@ include <BOSL2/std.scad>
cuboid(100, rounding=20);
```
We can round the edges aligned with one of the axes, X, Y, or Z:
Cube-like objects have six named faces.
```openscad-3D
include <BOSL2/std.scad>
cuboid([100,80,60], rounding=20, edges = "Z");
```
![](https://github.com/BelfrySCAD/BOSL2/wiki/images/attachments/subsection-specifying-edges_fig2.png)
You can round just the edges on one of the faces. Here we're rounding only the top edges:
You can round all the edges on one of the faces. Here we're rounding only the top edges:
```openscad-3D
include <BOSL2/std.scad>
@ -48,17 +61,6 @@ include <BOSL2/std.scad>
cuboid([100,80,60], rounding=20, teardrop = 45, edges = BOTTOM);
```
We can round only the edges aligned with one of the axes, X, Y, or Z:
```openscad-3D
include <BOSL2/std.scad>
cuboid([100,80,60], rounding=20, edges = "Z");
```
If you want to round selected edges you can specify which edges using combinations of the named directions **LEFT, RIGHT, TOP, BOT, FWD, BACK**. See [Specifying Edges](https://github.com/BelfrySCAD/BOSL2/wiki/attachments.scad#subsection-specifying-edges) for more details.
![](https://github.com/BelfrySCAD/BOSL2/wiki/images/attachments/subsection-specifying-edges_fig1.png)
It is possible to round one or more of the edges while leaving others unrounded:
@ -74,6 +76,28 @@ include <BOSL2/std.scad>
cuboid([100,80,60], rounding=20, except = TOP+FRONT);
```
You can also specify which edges to round using a 3x4 array, where each entry corresponds to one of the 12 edges and is set to 1 if that edge is included and 0 if the edge is not. The edge ordering is:
[
[Y-Z-, Y+Z-, Y-Z+, Y+Z+],
[X-Z-, X+Z-, X-Z+, X+Z+],
[X-Y-, X+Y-, X-Y+, X+Y+]
]
```openscad-3D
include <BOSL2/std.scad>
cuboid([100,80,60], rounding=20, edges = [[1,0,1,0],[0,1,0,1],[1,0,0,1]]);
```
Similarly, you can use an array to exclude selected edges from rounding:
```openscad-3D
include <BOSL2/std.scad>
cuboid([100,80,60], rounding=20, except = [[1,0,1,0],[0,1,0,1],[1,0,0,1]]);
```
###Negative Rounding
You can fillet top or bottom edges by using negative rounding values. Note that you cannot use negative rounding values on Z-aligned (side) edges.
```openscad-3D
@ -81,7 +105,7 @@ include <BOSL2/std.scad>
cuboid([100,80,60], rounding=-20, edges = BOTTOM);
```
If you do need to add a fillet on a Z-aligned edge, use [fillet()](https://github.com/BelfrySCAD/BOSL2/wiki/shapes3d.scad#module-fillet):
If you need to add a fillet on a Z-aligned edge, use [fillet()](https://github.com/BelfrySCAD/BOSL2/wiki/shapes3d.scad#module-fillet):
```openscad-3D
include <BOSL2/std.scad>
@ -90,6 +114,8 @@ cuboid([100,80,60], rounding = -10, edges = BOT+FRONT)
fillet(l=60, r=10, spin=180);
```
###Chamfering
Chamfering the edges of the cuboid() can be done in a manner similar to rounding:
```openscad-3D
@ -106,7 +132,7 @@ cuboid([100,80,60], chamfer=20, edges = "Z", except = FWD+RIGHT);
##Prismoid Rounding
The [prismoid()](https://github.com/BelfrySCAD/BOSL2/wiki/shapes3d.scad#functionmodule-prismoid) differs from the cuboid and cube in that you can only round or chamfer the vertical(ish) edges using the built-in parameters. For those edges, you can specify rounding and/or chamferring for top and bottom separately:
The [prismoid()](https://github.com/BelfrySCAD/BOSL2/wiki/shapes3d.scad#functionmodule-prismoid) differs from the cuboid and cube in that you can only round or chamfer the vertical(ish) edges using the built-in parameters. For those edges, you can specify rounding and/or chamfering for top and bottom separately:
```openscad-3D
include <BOSL2/std.scad>
@ -240,11 +266,23 @@ diff()
```
##Rounded Prism
You can construct cube-like objects, as well as a variety of other prisms using [rounded_prism()](https://github.com/BelfrySCAD/BOSL2/wiki/rounding.scad#functionmodule-rounded_prism). The unique feature of [rounded_prism()](https://github.com/BelfrySCAD/BOSL2/wiki/rounding.scad#functionmodule-rounded_prism) is the ability to use continuous curvature rounding. Rather than using constant radius arcs, continuous curvature rounding uses 4th-order Bezier curves. For complete details on how this works see [Types of Roundovers](https://github.com/BelfrySCAD/BOSL2/wiki/rounding.scad#section-types-of-roundovers).
You can construct cube-like objects, as well as a variety of other prisms using [rounded_prism()](https://github.com/BelfrySCAD/BOSL2/wiki/rounding.scad#functionmodule-rounded_prism). In this tutorial we're concentrating on rounding cubes, but [rounded_prism()](https://github.com/BelfrySCAD/BOSL2/wiki/rounding.scad#functionmodule-rounded_prism) has capabilities that extend well beyond cube-like objects. See the rounded_prism() examples to learn more.
Two parameters control the roundover k and joint. The joint parameter is specified separately for the top, bottom and side edges; joint\_top, joint\_bot, and joint_sides.
A feature unique to [rounded_prism()](https://github.com/BelfrySCAD/BOSL2/wiki/rounding.scad#functionmodule-rounded_prism) is that it uses continuous curvature rounding. Rather than using constant radius arcs, continuous curvature rounding uses 4th-order Bezier curves. For complete details on how this works see [Types of Roundovers](https://github.com/BelfrySCAD/BOSL2/wiki/rounding.scad#section-types-of-roundovers).
Two parameters control the roundover k and joint. The joint parameter is the distance from where the rounding starts to the unrounded edge. The k parameter ranges from 0 to 1 with a default of 0.5. Larger values give a more abrupt transition and smaller ones a more gradual transition.
Parameters of a "smooth" roundover, with k=0.75.
![](https://github.com/BelfrySCAD/BOSL2/wiki/images/rounding/section-types-of-roundovers_fig3.png)
Parameters of a "smooth" roundover, with k=0.15. The transition is so gradual that it appears that the roundover is much smaller than specified. The cut length is much smaller for the same joint length.
![](https://github.com/BelfrySCAD/BOSL2/wiki/images/rounding/section-types-of-roundovers_fig4.png)
The joint parameter is specified separately for the top, bottom and side edges; joint\_top, joint\_bot, and joint_sides.
The k parameter ranges from 0 to 1 with a default of 0.5. Larger values give a more abrupt transition and smaller ones a more gradual transition. A k value of .93 approximates the circular roundover of other rounding methods.
If you want a very smooth roundover, set the joint parameter as large as possible and then adjust the k value down low enough to achieve a sufficiently large roundover.
@ -256,41 +294,54 @@ rounded_prism(rect(20), height=20,
joint_top=10, joint_bot=10, joint_sides=9.99, k = 0.5);
```
A large joint value and a very small k value:
Here we're using the same cube size of 20, setting the joint paramater to 10 and varying the k parameter.
```openscad-3D
```openscad-3D;ImgOnly NoScales Med VPD=170 VPR=[75,0,25]
include <BOSL2/std.scad>
include <BOSL2/rounding.scad>
rounded_prism(rect(20), height=20,
joint_top=10, joint_bot=10, joint_sides=9.99, k = 0.01);
left(30) {
rounded_prism(rect(20), height=20, joint_top=10, joint_bot=10, joint_sides=9.99, k = 0.15);
move([0,-12,-12]) xrot(90) color("black") text3d("k=0.15", size=3, h = 0.01, anchor= CENTER);
}
right(0){
rounded_prism(rect(20), height=20, joint_top=10, joint_bot=10, joint_sides=9.99, k = 0.5);
move([0,-12,-12]) xrot(90) color("black") text3d("k=0.5", size=3, h = 0.01, anchor= CENTER);
}
right(30){
rounded_prism(rect(20), height=20, joint_top=10, joint_bot=10, joint_sides=9.99, k = 0.75);
move([0,-12,-12]) xrot(90) color("black") text3d("k=0.75", size=3, h = 0.01, anchor= CENTER);
}
```
A k value of 0.3
You can match the cicrular roundover of cuboid() by setting the joint values to the rounding used in cuboid() and setting the k value to 0.93:
```openscad-3D
include <BOSL2/std.scad>
include <BOSL2/rounding.scad>
rounded_prism(rect(20), height=20,
joint_top=10, joint_bot=10, joint_sides=9.99, k = 0.3);
```
A k value of 1:
```openscad-3D
include <BOSL2/std.scad>
include <BOSL2/rounding.scad>
rounded_prism(rect(20), height=20,
joint_top=10, joint_bot=10, joint_sides=9.99, k = 1);
```
A k value of 0.93 approximates the circular roundover of other rounding methods:
```openscad-3D
```openscad-3D: Med
include <BOSL2/std.scad>
include <BOSL2/rounding.scad>
rounded_prism(rect(20), height=20,
joint_top=4, joint_bot=4, joint_sides=4, k = 0.93);
right(30)
cuboid(20, rounding = 4, $fn = 72);
cuboid(20, rounding = 4, $fn = 72);
```
[](https://github.com/BelfrySCAD/BOSL2/wiki/masks3d.scad#module-rounding_edge_mask)
The joint size can be set to different values for each side of the prism:
```openscad-3D
include <BOSL2/std.scad>
include <BOSL2/rounding.scad>
rounded_prism(rect(20), height=20,
joint_top=4, joint_bot=3, joint_sides=[2, 10, 5, 10], k = 0.5);
```
Likewise, k can be set to different values for each side of the prism:
```openscad-3D
include <BOSL2/std.scad>
include <BOSL2/rounding.scad>
rounded_prism(rect(20), height=20,
joint_top=3, joint_bot=3, joint_sides=8,
k_top=0.5, k_bot=0.1, k_sides=[0,0.7,0.3,0.7]);
```