Geometry selection for milling operations
The profiles and the area to be machined are calculated taking into account the selected geometry, the tool orientation and the shape of the stockmaterial.
It's critical to define precise stock dimension at start since they will be used all along the toolpath creation.
To better understand the different behaviours , in this post will be shown several selection examples.
Enable geometry selection
First you need to activate the selection to associate geometry to current machining operation.
Turn ON the selection check box like this.
Once you done, turn OFF the selection mode so you can't add or remove additional geometry by mistake.
To turn OFF the selection , uncheck the box or press the [mouse right button] when the cursor is on the viewport.
Please take a look also at the CHAIN SELECTION post , if you didn't already
TODO > Dedicated post on geometry selection control.
Model edge selection
Try to select a single edge , in this way :
The software will extend the selected profile to the stock area border, defining an area to machine ( in blue ), like this.
It will also try to determine the side where the model part is located, machining the free side.
Is it possible to switch the machined side by clicking the arrow located on the selected entity :
You can switch sides also from geometry selection control, under options menu, and click on [INVERT MACHINING SIDE].
Just for demonstration purpose i switched the machined side to obtain this area.
I can see i'm machining all the part model .
I have also the option to recognize the part model and compensate the machining area.
Turn ON the option "Enable 3D Model Compensation" from roughing operation properties screen.
This option will exclude the area of the 3D model.
See the image below, the area occupied by the 3D model is not machined anymore.
Union of projected profiles
The selected profiles are projected with tool orientation direction onto bottom plane.
In this case the bottom level is -10mm from model bottom.
I have selected 2 edges and they are projected onto that plane.
Since they have a common endpoint, the profiles are united in a single profile.
Face selection
If you select the face area , the outer face boundary will be the area to be machined.
Depending on adjacent faces, they are determined open and closed side.
The closed side will be used also for finishing operation.
Any open area inside is machined as well.
If you instead you want to skip some inner area, just select the related edges of inner profile.
Like this :
You can see the blue area is not anymore on the selected inner profile. And that area is not processed anymore with the
2D Open Profiles
The behaviour of selecting 2D open profiles is identical to selecting edge from 3D part model.
Subcurve selection
Is possible select only a section of selected profile.
From Geometry menu > "Create a subcurve from this contourn"
Enable the subcurve creation and pick a start and a end point.
This selection will considered as an open profile,
So for rounghing operation , the subcurve will be extended to stock border.
The finishing operation will machine only the indicated profile.
![](http://d33v4339jhl8k0.cloudfront.net/docs/assets/5bc4545b042863158cc767ed/images/636120857678db1f1186a428/file-kZ2LXt8KWL.png)
Please notes that faces and edges features are available only on 3D structured models imported from STEP or IGES files.
In STL will be not possible use the method showed in this post. Since the STL , in short , are composed just by vertices .
They not contain any precise information on model feature. More info on STL Fil