unable to pad sketch created with basefeature as external geometry

[juo]

Hi,

I am trying to create a "slider-bracket" for a raspberry pi using an imported STEP file.

I performed the following steps:

• import step file

• create a BaseFeature by selecting imported STEP object and creating a body

• creating a sketch on one of the faces of the BaseFeature

• using edges of the BaseFeature as external geometry for contraining the sketch

• trying to pad the sketch

When I try to pad the sketch, I get the error "Pad: Result has multiple solids. This is not supported at this time."

I tried creating a new body and sketching there, but I cannot select the BaseFeature for external geometry.

How can I use the imported BaseFeature for constraining my sketch (and create solids from the sketch)?

This is the model tree:

210720_234814.png (9.18 KiB) Viewed 714 times

edit:

I have now used a shapebinder as a reference for my sketch and was able to create a pad.

210721_013858.png (11.65 KiB) Viewed 711 times

How can I now constrain the placement of the sketch/pad relating to a face of the shapebinder. (6mm z offset)?

210721_013758.png (24.53 KiB) Viewed 711 times

Thanks,
Juo

Code: Select all

OS: Manjaro Linux (i3/i3)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.24291 (Git)
Build type: Release
Branch: makepkg
Hash: 7b5e18a0759de778b74d3a5c17eba9cb815035ac
Python version: 3.9.5
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.0
Locale: German/Germany (de_DE)

[chrisb]

Hi and welcome to the forum!

How can I now constrain the placement of the sketch/pad relating to a face of the shapebinder. (6mm z offset)?

You can modify the z component of the Attachment Offset.

[freedman]

You could also use the map-to-support function and select the face of the shapebinder, not currently the best choice because of the topo-naming issue but it's still nice to know how.

[TheMarkster]

You could also use the map-to-support function and select the face of the shapebinder, not currently the best choice because of the topo-naming issue but it's still nice to know how.

I think it will be safe to map directly to the faces of that shapebinder because the referenced object is never going to change. Even if you do something like a boolean cut in part workbench the original object isn't changed; only a new cut object is created. It is in the mapping directly to subsequently created faces where potentially problems could emerge due to topological naming.

[juo]

Thanks!

I attached the sketch to XZ plane and used z-offset:

210722_005956.png (33.71 KiB) Viewed 606 times

I do have another problem now: after finishing and printing the design, I would like to alter a sketch/pad that sits in the middle of the object tree (I would like to make the supporting base for the pi bigger in order to accomodate a screw):

210722_005732.png (29.73 KiB) Viewed 606 times

210722_005809.png (42.77 KiB) Viewed 606 times

How could I alter the diameter of the pad without breaking the whole file?

When I just alter the diameter in the sketch, the pad gets bigger(can toggle Pad002 visibility), but the change doesn't carry over to the final design (toggle Chamfer001 visibility).

Here is the dependency graph:

dependency_graph.png (211.43 KiB) Viewed 597 times

Thanks again,
Juo

[GeneFC]

Without a file I cannot be sure, but I suspect you can simply add the larger pad at the end of the tree. Just let it overlap the existing pad. Don't do anything to change the too-small pad at all.

Everything will automatically merge together and should print properly.

Gene

[juo]

That sounds good, Thanks!

[freedman]

Any time I want to change an early feature or sketch I do a "save as" and add a number to my design, then make the change and see what happens. I do a lot of save-as because of my old Solidworks usage when it would crash 5 times a day. I do it out of habit now, I think my last FreeCAD complex mold design I was up to "rear_cap122", so 122 incremental saves over many weeks. I delete most all of them in the end.

[chrisb]

FreeCAD can do such numbered backups all by its own. To be configured in Preferences->General->Document. Set the maximum number of backup files to a high number and let FreeCAD do the rest. And enable the auto recovery with a short time, just in case FreeCAD crashes.