Selection is not in Active Body

[ickby]

Currently mirror only works on features. The PArt way is currently the only possible one. There is a feature request for this on the tracker already, maybe once it will be implemented.

[NormandC]

In PDWB there is a tool "create a mirrored feature". Is it the only way to mirror an object? (It's not at all convenient to mirror one feature after another step-by-step. And can't copy fillet for example)
May be I can copy body and mirror it, and then boolean 2 bodies?

In 0.17-dev, you can actually select more than one feature for a transformation feature. The problem is that selecting more than one is not intuitive.

Here's what I know works (that's what I came up with by testing, I don't know if there's any other working method):

1. Select a single feature then launch the transformation feature you need (mirrored, linear/polar pattern, multitransform)
2. In the Tasks panel, click on the "Add feature" button
3. Here comes the tricky part: you need to make the feature you want to select visible in the 3D view, because that's the only way to select it; so switch to the Model tab, then click on the feature you want and hit spacebar: the model shown in the 3D view will roll back to that particular feature
4. Click on the model in the 3D view
5. Switch back to the Tasks panel, you will see the feature added in the list under the transformation parameters widget; the model shown in the 3D view will go back to the preview for the active transformation feature.
6. Repeat from step 2 as needed until you have selected all the features you want.
7. Adjust the parameters as needed and complete the operation.

Freecad 0.17 11129(Git)

In the future, please report your complete FreeCAD info as explained in the forum rules. Sometimes (quite often) it's relevant to know your OS and library versions your version of FreeCAD is compiled with.