[solved] - Toolpath Skips Block

[Grafpaper]

I created a drawing of boxes; each box is a block. I truncated some of the boxes to fit the work envelope on my CNC machine. When I created the toolpath only the truncated boxes and a box that was edited into a smaller box were part of the tool path, none of the blocks were included. I tried exploding one block to see it that made a difference – it didn’t.

I’m trying to determine why the blocks are skipped.

toolpath.jpg (99.31 KiB) Viewed 5795 times

[andrew]

You'd have to explode the blocks and then re-create the toolpath. Blocks cannot be used as basis for toolpaths as they can contain any combination of entities that might or might not be suitable for a toolpath.

Note also that one of the blocks has been inserted twice in the same spot.

[Grafpaper]

Thank you for the information. Exploding the blocks worked. I had to delete the previous toolpath and generate a new one.

[newyd_cnc]

On this very subject, I find myself obliged to group objects in order to move them effectively in my layout before computing toolpaths for CNC cutting.
I say grouping entities which in QCAD way that means creating blocks. However as it stands, using blocks turns out to be cumbersome becaue I then have to explode the blocks before being able to computing toolpaths on the items that were contained in the blocks. Typically my CNC cut files include 50+ blocks each composed of 10+ entities.

Now it turns out to be cumbersome because if you then want to tweak one former block actual position you have to select each item individually and be careful not to leave anything behind in the selection etc ...

Now I understand that once the items are grouped in a block, the block doesn't "offer" an entry point for the toolpath algorithm to work with.

Wouldn't it be possible then to introduce the notion of grouped selection as a mere set of selected objects, without the notion of unity of block, insertion point , etc... . Since you can select say 4 items and apply to the selected items a toolpath computation (no problem finding an entry point for the toolpath in that case) couldn't it be possible to group the selection (i.e. remember several selected object in one only selection) and handle basic transform operations (at least translations and rotation WRT a simple extremity point or other ) and toolpath computations?

[CVH]

@ newyd_cnc,

I extract CAM related data to a working file to process with QCAD/CAM.
From a master file I can then create as many CAM files as desired, with different things and/or as several revisions.

Basically: Don't clutter your CAM source drawing with unnecessary items.
And on the other hand: All CAM related (CAM-Blocks with custom Props, CAM-Layers) is of no meaning in a master drawing.

For CAM preparation I tend to group source drawing entities in layers by intended toolpath.
Another type of grouping than Blocks is not supported by QCAD.
Layers have much more attributes to play with: Hiding, Freezing, Locking, ...
And can be stacked in a hierarchic manner.

If you want to move all visible then Select All (TA).
Selecting all on a certain layer can be done in the Layer List with Y+ (Remind that this adds to an existent selection, if any)

And another reason to chop up things is that I have to keep my G-Code files limited to a certain (large) amount of text lines.
My designs have highly detailed shapes and on top, they include spiral pocketing with tiny engraving points.
Once beyond the limit my CNC controller doesn't display the current text lines in process ... [Huge file]

Bottom line: I don't have a purpose for Blocks.
And I don't edit in a later stage, I make revisions.
Chopping and layering is a method that works well and I've made it a habit.

Regards,
CVH

[newyd_cnc]

Thank you for your helpful feedback.

I'd be grateful if you could share how you would handle a project like mine? See the CAD below: it includes 58 objects to be CNC cut. Each object includes 5 lines, 2 circles, 2 splines and 5 arcs. It is quite diffuclt to select an object when the others are packed tighlty as in my file.

cad.png (42.25 KiB) Viewed 2795 times

Would you go for one layer per object? or else?

Below is the CAM which looks fit for my purpose, however I wouldn't refrain from tweaking some object positions.

CAM_toolpath.png (107.26 KiB) Viewed 2795 times

Thank you for your ideas and suggestions

[CVH]

I'd be grateful if you could share how you would handle a project like mine?

I see your problem.
Reading another topic on groups it seems that ACAD has something like that.
It does not entirely mimic the Block functionality and I read about issues with that.

In my wish list I added an entry for some similar functionality.
Adding a parameter or a custom tag/property so that we can select items of a group together.
I think it will not be that hard to add a selection change listener and then filter all drawing entities based on the selected tags.

But it is way down in my ToDo list.

They are all different shapes I presume or probably pairs.
One could create a layer for each ... With a sub-layer L and R for example.

Regards,
CVH

[newyd_cnc]

Hello CVH,

it was indeed useful to discuss my project with you as I got to know about sub-layers that I wasn't previously aware of. That can indeed prove to be a helpful feature.

About grouping, yes ACAD has something like that (but as you say a little bit wonky) while Rhino3D has a very good one. It operates as a simple collective selection tool.

Best regards
LBR

[CVH]

About grouping, yes ACAD has something like that (but as you say a little bit wonky) while Rhino3D has a very good one. It operates as a simple collective selection tool.

@ newyd_cnc,

Have successfully implemented a entity group selection tool ... Beta version ...
It is fairly similar as the 2D Centroids listener, you activate or deactivate it.
Almost a copy/paste - Rename - Implement selecting.

Works like a charm.
The selection key is a Custom Property called 'Group ID' intended for a value upwards from zero.
But why not a name because all is textual? Why not groups with subgroups?

Tinkering further ...
I need to block signals too because now it runs again after it has updated the selection itself.
Processing a large amount of visible entities and/or a large selection is fast but not that fast to do it twice by default.

Regards,
CVH