CAD Forum

Hi, everyone,

I work with drawings that have to be fully adaptive. For this, I commonly use numerous constrains and parametric dimensions. For several years, I used Autodesk Inventor (as was taught in university). However, when dealing with 300+ constraints and dimensions, Inventor starts lagging and freezing when I change one of them as the whole drawing has to be recomputed. Recently, I tried Autodesk AutoCAD and encountered the same problem; moreover, their documentation says, that 200 constraints is already too much (https://www.autodesk.com/support/techni ... aints.html). I was surprised when I checked AutoCAD examples and their elements are completely free to move across the drawing.

I wonder, if there are software products that won't go mad in my case. I am going to try SOLIDWORKS next, as it seems not to have these problems.

Solidworks can definitely handle large assemblies, but your modelling practices will have a large effect on how fast/slow it is. (I say this as someone who started with bad practices and slow assemblies, but learned the methods that solidworks prefers.)

There are some threads on here discussing both large drawings and optimizing Solidworks. A little searching should provide you with much information.

Alin is very knowledgeable in that area. Here is one of his videos.

Generally someone eventually is going to introduce you to the concept of best practice. It is probably considered "best practice" to break that sketch up into smaller sections, and allow each section to be somewhat self-contained.

Not to say SW or any other software couldn't do it, but people generally don't do it because there are better ways of doing things. 300 sketch relations in a single sketch? I don't know anyone who actually does this, and if they did, I'd certainly suggest that they do it some other way.

In SW and most 3D modelers, the sketch is really meant to create features. Features are generally smaller ideas, and you put a part together from many of these smaller ideas. So you might wind up with hundreds or thousands of sketch relations and dimensions within a single part, but probably not in a single sketch.

Single big sketches do bog down. I don't know where the limit is. Most people don't run into the limits here because all of that size is distributed across multiple features or even multiple parts.

Big sketches are slow and are difficult to troubleshoot. If you overdefine something, you've got a big mess on your hands, and you're much more likely to just trash a big section. Where if you have a series of smaller sketches, everything is easier.

I'm going to guess the Inventor people also told you this.

Maybe you could be more specific about what you are trying to do.

perotto wrote: ↑Thu Sep 26, 2024 4:28 am Hi, everyone,

I work with drawings that have to be fully adaptive. For this, I commonly use numerous constrains and parametric dimensions. For several years, I used Autodesk Inventor (as was taught in university). However, when dealing with 300+ constraints and dimensions, Inventor starts lagging and freezing when I change one of them as the whole drawing has to be recomputed. Recently, I tried Autodesk AutoCAD and encountered the same problem; moreover, their documentation says, that 200 constraints is already too much (https://www.autodesk.com/support/techni ... aints.html). I was surprised when I checked AutoCAD examples and their elements are completely free to move across the drawing.

I wonder, if there are software products that won't go mad in my case. I am going to try SOLIDWORKS next, as it seems not to have these problems.

what is the actual deliverables environment? Inventor is a 3D CAD system, but it kinda sounds like you're actually looking to do only-2D stuff.

matt wrote: ↑Fri Sep 27, 2024 10:29 am Generally someone eventually is going to introduce you to the concept of best practice. It is probably considered "best practice" to break that sketch up into smaller sections, and allow each section to be somewhat self-contained.
...
Maybe you could be more specific about what you are trying to do.

I completely agree about dividing the complex project into multiple sketches, but it will not work in my case. Here is an example of my ordinary project: https://ibb.co/dPdzWQ5. It is a drawing of a gear that is fully adaptive. Whenever I change a single dimension, the whole thing changes - this process really takes some time to accomplish.

Jim Elias wrote: ↑Fri Sep 27, 2024 10:46 am what is the actual deliverables environment? Inventor is a 3D CAD system, but it kinda sounds like you're actually looking to do only-2D stuff.

Surely, Inventor is more suitable for 3D, but, as I mentioned, it was my primary CAD system carried from university, where we used it for drawings at the same time. I am seeking for a similar software without problems that are specific to Inventor, like difficulties with handling lots of constraints and inability to copy hatching or duplicating a sketch.
I tried AutoCAD and it has the same problems with handling too many constraints.
Solidworks works way faster, but is unable to copy a pattern or bind a note to geometry

perotto wrote: ↑Fri Sep 27, 2024 12:30 pm Surely, Inventor is more suitable for 3D, but, as I mentioned, it was my primary CAD system carried from university, where we used it for drawings at the same time. I am seeking for a similar software without problems that are specific to Inventor, like difficulties with handling lots of constraints and inability to copy hatching or duplicating a sketch.
I tried AutoCAD and it has the same problems with handling too many constraints.
Solidworks works way faster, but is unable to copy a pattern or bind a note to geometry

You've got some basic facts incorrect. And you seem set on one particular type of solution while trying to use software in a way that it wasn't intended to be used. So best of luck, I hope you find what you have determined that you need.

There's a lot of symmetry involved. Have you tried simplifying your sketch? People have been making gears for a long time without being stymied by this problem.

perotto wrote: ↑Fri Sep 27, 2024 12:21 pm I completely agree about dividing the complex project into multiple sketches, but it will not work in my case. Here is an example of my ordinary project: https://ibb.co/dPdzWQ5. It is a drawing of a gear that is fully adaptive. Whenever I change a single dimension, the whole thing changes - this process really takes some time to accomplish.

The best method here would be, to set up your gear assembly as 3D models, then make your diagram as a drawing file based on the 3D model. You then control the gear characteristics in 3D and the resulting drawing will update to suit. Trying to create a complex stand-alone 2D drawing in a 3D system is a non-starter.

Parametric AutoCAD is fine for lots of things, but it's very limited with spline-type forms (such as involutes)