Sketch Blocks

malcolm_smith_1

In Autodesk Inventor there is a handy feature called sketch blocks, whereby you can save a part or all of a sketch as a 'block' (AutoCAD style) and later insert it into the same or other sketches within the part you are modelling. This is very handy if you are making, say, a frame with steel sections as the blocks are very easy to locate orient whichever way you like, whist retaining the original section geometry. How would you go about doing this in Onshape? Is there a 'sketch block' method or anything similar?

brucebartlett

I would create a document with a series of sketches in a part studio. I'd try constraints to reference only the bits I want to block out. Then just load this doc and RMB copy to get the bits/block of sketch detail to be used and RMB paste in the new doc. 

here's an example dochttps://cad.onshape.com/documents/0a355a367a4941eca0d90a0f/w/3d4fdaaf6b77419db7fa309b/e/8b85f21654054aa4bffb82ac

malcolm_smith_1

Thanks Bruce, I just had a quick look at that document. The problem is the same as it is in Inventor if you don't use sketch blocks. The sketches are constrained, as they should be, so when you copy and paste them, you can't re-orient them (as far as I know) without a lot of effort, by either changing the local co-ordinate system or by breaking the constraints. With sketch blocks, the block has a single insert point which can be located anywhere and you can freely rotate the block before constraining it in the required position and orientation.

mahir

@malcolm_smith_1, there's nothing dictating that you have to fully constrain your sketch entities. Add just enough constraints to keep the block entities together. Don't use any horizontal or vertical constraints which would keep you from rotating the block later. Hopefully, OS gets real sketch block support at some point.

brucebartlett

malcolm_smith_1 said:

The sketches are constrained, as they should be, so when you copy and paste them, you can't re-orient them (as far as I know) without a lot of effort, by either changing the local co-ordinate system or by breaking the constraints. 

Generally, the sketches in that doc have been done so you get all the constraints if copy all the parts and then just position and orientate in your new doc with 2 additional constraints. It works ok for me. 
H

malcolm_smith_1

I'm not sure yet how Onshape deals with copied sketches, but one of the differences/advantages of using sketch blocks is that they are inserted as instances, so any change made to the original sketch is made to all of the inserted blocks. Generally, copies are independent of each other so updating one does not affect the copies.

brucebartlett

malcolm_smith_1 said:

I'm not sure yet how Onshape deals with copied sketches, but one of the differences/advantages of using sketch blocks is that they are inserted as instances, so any change made to the original sketch is made to all of the inserted blocks. Generally, copies are independent of each other so updating one does not affect the copies.

Yes, copies are independent, so there is no ability to update from the original.

michael_richards609

+1 for sketch blocks

Axel_Kollmenter

Hi @malcolm_smith_1

I do it this way: I have created some sketch blocks that I use over and over again (partstudio saved with only the sketch I want) Then in another document I use the Point Derive feature from @Alex_Kempen . This allows you to load sketches and parts from other documents into a partstudio.

This works great! If you want to have an explanation video I can create one for you.

I have asked the same question before. Perhaps you can read through the contribution times:

https://forum.onshape.com/discussion/18176/sketchblocks#latest

toshana_james

sketch blocks are needed for rapid problem solving where you do not want to sit and constrain everything and eyeball a sketch group or freeze it relative to each selected entity so as to manipulate it as you like within the same sketch, this is a powerful functionality that can really aid the rapid conception phase, please consider adding this. 

S1mon

I would love sketch blocks too, but keep in mind you can create a bunch of unconstrained sketches in a part studio (or studios) and insert them into an assembly where you can add mates if you want.

malcolm_smith_1

The thing with sketch blocks is that they can be used as multiple instances within a single sketch, just like blocks in an AutoCAD drawing. Say you have a single sketch with multiple structural sections in it as blocks. If you edit the block and change the size of the section, they all update. This is very handy for conceptual work. It's a bit hard to explain just how useful this is. It's quick and easy.

S1mon

@malcolm_smith_1

I completely understand. I used sketch blocks for years in Solidworks. I would love to see them in Onshape.

Depending on your end goal, for now, you can assemble a ton of sketches into an assembly and move them around. You can modify the dimensions back in the part studio and the assembly will update. It's more awkward than in a sketcher because of the effort of the context switching, but many of the things you're talking about are possible now.

malcolm_smith_1

Absolutely, you don't 'need' sketch blocks, but it's a good workflow.

yilong_fan160

I cannot believe its been 5 years, and yet there is nothing done to it.
for some companies you 100% need sketch blocks, when you are given a very complex pattern, as asked to scale rotate as a whole.

The fact that when you move things, the pattern could slightly change unexpectedly is absolutely a horror then you are to cut the pattern on the $6000 sheet.

Ste_Wilson

I cannot believe you dusted off a six-year-old thread just to complain for your first post.
How about instead of an angry ranty type post create a new thread, outline your use case, explain your problem and solutions you have tried, reference where you have looked on the forum and ask if there have been any developments/ ways of working/ or feature scripts.  Is there an existing improvement request?
You might get a more positive response from the community and the developers.

rick_randall

Am I missing something ? Why don't you use triad manipulator to move copied sketches? It automatically drops offending constraints when used.

shawn_crocker

@yilong_fan160
Grouping of sketch entities would be nice.  Grouping sketch entities does provide the user more confidence that the original positioning of the grouped entities has not changed accidentally.  It would be nice to be able to do some sort of derive within a sketch context that links to another sketch within the part studio or from a different part studio.  The way I get around the absence of sketch blocks and still allow myself the same level of confidence I will not unintentionally change the sketch entities is by using surfaces.  I will often create some sketch somewhere that I want to use again in other places possibly at scale or translated.  I will then make the sketch into a surface part.  I will then usually derive the surface into the part studio I want to work with it and use the surface to extrude or generate sketch geometry within other sketches.  It actually works really well.