Give a thickness to Rhino complex surfaces

Anyone know an external software (e.g., SolidWorks) that can give a thickness to rhino surfaces?

Your question isn’t clear.
Pls add more detail about what’s your workflow.
Why you have to add thickness outside when Rhino has a great Offset surface solid options?

Btw exporting as step any other cad would do thickness… But a good Rhino surface is needed.

1 Like

Hello, I would like to 3D print by adding thickness to the surface. I want to make it solid in a solidworks environment. However, it’s hard to make the model close. If there is any other software with which I can easily give a thickness to all rhino surfaces, that will be easy.

So once you have your model closed into a solid, for 3D printing it doesn’t need to be ‘thickened,’ the slicer can do it.

To figure out why your models aren’t closing up we need to see examples, there’s not much in the way of magic 3rd-party tools to just “fix” a junky model. Of course there is the ShrinkWrap function in V8, but your first line of defense is proper model construction in the first place.

1 Like

Attached is the model. Please have a look
V1 of hull 2.3dm (1.2 MB)

The model isn’t a closed polysurface so this would need to be tackled first.

The input curves aren’t symmetric, their endpoints do not line up and some of the curves have duplicates… Overall a lot of problems…

Did you change tolerance to 0.01 on purpose? Well, I changed it back to 0.001 and fixed all your input curves. If you’re going to change the curves, you need to be more precise and make sure the end points match the surrounding curves or have clear overlaps.

I’ve used loft, sweep 1 and 2 to create a closed model.

The cutout side to side is done with a boolean subtraction. Note how the cutout surfaces have their normals. Instead of trying to match surface edges on the cutouts, I’d suggest to have overlapping geometry which will ensure your objects can be trimmed.

Shelling the hull to give a thickness is problematic due to the narrow and pointy surfaces. Your quick solution to get a closed offset polysurface is to rebuild the hull without the narrow surfaces and shell that. Delete the outside and subtract offsets of the side to side cutouts.

The two polysurfaces in the attached Rhino model join to a closed polysurface.

hull.3dm (2.3 MB)

1 Like

Hi thanks. Will you be able to email me the full model.

No. You can simply join the two polysurfaces in the Rhino model attached to my last post.

Hi Martin, Is there a command that can make split surfaces into one surface? I join, but it still shows split lines. when filet surface it effect. I just want to makethe attached surface to one surface without split lines
sample 1.3dm (1.1 MB)

Instead of trying to fix or rebuild what you have, I would build the whole top surface as one rectangle and then trim with boundaries.

Is there a command I can use to make edges round with a small radius? The filet surface is messy.

Wow, those simple shapes are actually made by surfaces with extremely dense control points. I suggest to use clean curves when you build your models, or rebuild the resulting surfaces either via ! _Rebuild or ! _RebuildUV.
Avoid using the ! _NetworkSrf tool, because it’s not accurate.

In case that you prefer to use the model provided by @martinsiegrist above, then you can get a simpler result by exploding the boat model, select all surfaces together and run ! _RemoveMultiKnot, then join them again.

Obviously, rebuilding the surfaces to make them much simpler will lead to a slight change of their geometry, but you can opt for some settings that are close enough to keep your design intent while also let you control the shape by manual control editing. Once you rebuild all primary surfaces, it’s recommended to untrim and extend them a bit, so that they will intersect each other and become ready for further trimming and joining together.

For example, here is the original side surface:

After ! _RemoveMultiKnot (still joinable within the 0,001 mm tolerance):

After ! _Rebuild (slight deviation up to 0,446113 mm):

The settings I used for ! _Rebuild of this particular surface (other surfaces may require different settings). Note that the deviation is less than 1 mm:

In case that you can accept even higher deviation, you can achieve relatively the same shape with a single-span surface consisting 6 control points along the length of the boat.

As for the input curves, I found that they are too wavy and lead to improper surfacing. Here is a comparison between the original main top curve and one that I rebuilt to degree 4 with 5 control points. It’s also much smoother and you will notice that from side view it’s no longer wavy, because I made it completely straight by projecting from top view its control point over a flat plane (the latter I built from a straight line between both ends of the original curve).

Original curve from side view (Perspective, not actual isometric view):

Rebuilt curve from side view (Perspective, not actual isometric view):

Original curve from top view (Perspective, not actual isometric view):

Rebuilt curve from top view (Perspective, not actual isometric view):

You can build relatively the same surface with just 5 control points and degree 4 along the length of the boat (see my example below). It’s much, much easier to edit the shape that way, not to mention that degree 4 lets you keep the smoothness of the reflections.

Degree 4 with 5 control points.3dm (139.2 KB)

My other two recommendations are:

  1. Use the coordinate system properly, i.e. Y-axis must be the length, while X-axis is the width. Your boat is oriented along the X-axis instead of Y-axis. While this is no actual issue with the geometry itself, it gets confusing, because, for example, the left view will not show the boat from the side.

  2. If you are going to manually edit the control points, try to avoid degree 3 curves and surfaces with way too many control points. After editing, degree 3 surfaces tend to have “accelerated” regions that produce bad reflections. This is why it’s recommended to bump the degree to 4, because degree 4 surfaces always retain equal smoothness or flow of the shape.

Thanks Boby.

In the beginning the goal was to have a closed model so all I did was a very quick rebuild with the curves provided or some surface edges I duplicated. Then Emanuel asked for offset, combining surfaces and now fillets…

I agree it’s probably best to start from scratch with clean and simple curves.

1 Like

The standard practice for boats which I am aware of is X-axis is longitudinal, Y-axis is transverse, and Z-axis is vertical.

The standard practice in the automotive industry is X-axis is longitudinal, Y-axis is transverse, and Z-axis is vertical. This practice predates CAD.

This is not my experience, though it may depend on how far control points are moved and in what direction during “editing”.

Degree 3 curves and surfaces always “accelerate” in certain regions after editing. Of course, if you move one control point by 1 mm of a 5 meters long surface, the deviation will be small enough to not be noticeable. However, moving the same point by a greater distance will easily reveal the disadvantage of using Degree 3 curves and surfaces for direct point edit modeling of high-quality industrial design. a curve or surface with 5 control points with Degree 4 is far smoother than its counterpart with 5 control points with Degree 3.

As for Rhino’s World coordinate system, X-axis is transverse, Y-axis is longitudinal, Z-axis is height, hence my comment above.

In the past, many decades prior the coordinate system of CAD programs, people used different planes depending on the view:

  • From front view, X-axis was transverse, Y-axis was vertical, Z-axis was depth (longitudinal);
  • From side view, X-axis was longitudinal, Y-axis was vertical, Z-axis was depth (transverse);
  • etc… Just like in video games, where Z is always depth or normal projection to the camera view, despite that the majority of programs used to create video games have the same coordinate system as Rhino where Z-axis is always vertical.

To make things even more complicated, some parametric programs use Y-axis for the vertical coordinate.

Source for this claim about X-axis is transverse, Y-axis is longitudinal in Rhino? Is this based on the labeling of the default viewports?

The only Rhino command I’m aware of which is coordinate dependent is Hydrostatics which assumes “up” is positive Z.

Do you have any evidence that Rhino’s coordinate system is any different than what I described above?