Full Version: Expand a volume (offset object walls without creating a shell)

Hi,

What is the easiest way to expand the selected yellow object equally in all directions, similar to the offset operation, but without creating a hollow shell? Is it possible to move the surfaces along their normals? I want the radius to scale proportionally so it matches the original shape.

Thanks,
Frederik

Image Attachments:
Moi3D-Expand_Volume.jpg 

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If you simply scaled in 3d would that not accomplish what you need?

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Hi Frederik,

> What is the easiest way to expand the selected yellow object equally in all directions,
> similar to the offset operation, but without creating a hollow shell?

The offset command is the way to do that, it does not create a hollow shell, that's the Shell command.

You may need to break an object up into surfaces and offset the individual surfaces - MOI is not very good at handling sharp corners where surfaces need to be extended so that they meet up.

But you can use offset on those 3 surfaces that are tangent, tangent surfaces will naturally touch each other without needing extensions.


> Is it possible to move the surfaces along their normals?

That's exactly what offset does.

It looks like you may be able to offset curves and then extrude them to make a new piece, it would help if you could post the .3dm model file.

- Michael

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@Grendel,

re:
> If you simply scaled in 3d would that not accomplish what you need?

Scale will give a result like this, here scaling a curve up by a factor of 1.5 :



Every segment in the original curve will be present in the scaled result with each segment being 1.5x the length of the original.

Arcs in the scaled result do not have the same center point as the original.

Offset result is like this:



Lines that are tangent to their neighbors will keep the same length, arcs maintain the same center points, the overall length of the curve can change quite a bit.

- Michael

Image Attachments:
offset_result.png  scale_result.png 

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Thanks again!
I thought "offset" created a shell as well, but it was just the original volume that I was seeing on the inside – my bad.

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Have you tried the ScaleIndividual command ?

You can input a percentage

It works well on multiple parts also, scaling them each around their centre

cheers
shayne

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