I did a quick test, a basic M10 bolt with a cap head comes in at 2.62mb with the file compacted and the history removed.
A blank solid of the same size with no details is 20kb.

Is there a way to turn complex solids into dumb solids so as to reduce the file size?

Thanks Larry but this was more about reducing the size of all solids and not just threads, some programs utilize dumb solids which I think is a smart move (not an expert, just heard about it).

There is no doubt that direct modelling is the future of CAD, it makes sense.

I think the trick with direct modeling is to make the software user friendly/fast enough that it is faster to either make the modification on the fly or start from scratch then to go back and make the necessary modifications to existing features in the history. This isn't and won't be the case with some applications, but for many it is. For my particular line of work (dies + automated tooling) this is the case more often then not I find.

I find ViaCAD has awesome direct modelling capabilities. Just one of the great things about this software.

I still think Undo is necessary. However that form of history is very different from a parametric history. While constraints and be placed on and then you can direct edit, you still have to take the time to place those constraints on. Also, I believe you can constrain using driving dimensions with KeyCreator however I do not believe you can put on condition constraints like tangency on something you are editing directly. I could be wrong though.

Undo is necessary because it is one click and you are back to where you were rather then having to re-dit which could be many clicks to get back to where you were. Massive time saver. And keeping an Undo-Redo history should not be that taxing on the system though I know I am over-simplifying this to say the least.

I have tried KeyCreator and had meetings / demonstrations with there sales. This was about 1 yr ago. I wasn't overly impressed. I gave them one of my medium difficulty punches to modify and they struggled with it. They told me they couldn't do it in the time during the demonstration. That meant too long for me. From what I understand its very good for mechanical components but it's surfacing / filleting is not the strongest. That was my take at any rate.

Edited by user Wednesday, February 17, 2016 8:47:00 AM(UTC)  | Reason: Not specified

Why is undo necessary?
If I have placed 5 holes in a plate and realise the 3rd one is in the wrong place I do not use undo, I just move the 3rd hole to where I want it.
With parametric modelling there is a yesterday, a now and a tomorrow because you often have to plan ahead.
With direct modelling there is only a now, the system does not need to know where a hole used to be or where you may want to place it in the future, it only needs to know where it is now.

Think of any situation that you use undo and that undo can be corrected by simply adjusting the feature as required with real time direct modelling.
The real bonus is a lightweight system that is not being bogged down by useless information, we all have trouble understanding that undo and history is not required.

As for you not being impressed with Keycreator, you are not impressed with Solidworks and that is the finest system available apart from maybe Creo.
It all depends on what you want the system for, for myself Shark was the best system because of its speed and functionality but Keycreator is in a different league.

I think for what I do direct modelling is best as 90% of my machine designs are simple geometry I can modify easily using direct editing tools. Even for the more complex models, I know where I'm going and what I have to do to get there. There are lots of simple components so speed/less clicks is important.

For more organic shapes where a customer may want a surface here or there to have a greater degree of continuity or where complex surface changes may be requested and there aren't as many components I can see where history based has it's advantages.

Nobody has convinced me that a history tree is needed, if you move a feature and you want to move it back, you just move it back instead of using undo, I would like people to give me an example where history is needed?
To me a history tree is as outdated as CPU rendering.

Think about this one, take the counterbore function in Punch products, look at all the information boxes required to make the feature.
Now look at the direct modelling approach, two circles, one is pulled through and the other one is pulled to the required counterbore depth.
So it is all those information boxes vs two circles, which is easier on a CAD system?