I finally have some time to answer.
It's normal with uploaded images, unfortunately the forum engine doesn't allow for image resizing. That is why most of the time I use a hosting service, those generate the thumbnail automatically.aqua14 wrote:huhh... these pictures come out very big on the web page... trying better the next time.
By the way, nice work for a "beginner"! I haven't even modeled something as elaborate in FreeCAD yet!
I use a mid-range parametric CAD package at work, Solid Edge. So far I haven't modeled anything complex in FreeCAD, I'm still experimenting with its features.
Hey, nothing wrong with the method you used. Boolean operations have been used in 3D modeling for a long time.aqua14 wrote:Anyway, I was proud of myself to have virtually forged together two flat rods to form an angle iron mock-up,
maybe sometime later I will switch form the 'Smith' level to the 'Extruder' level, sounds somehow more elaborated...
Among other things.More interesting though is the question why the one or the other object is then not 'parametric'.
To be honest... had to rummage in my memories about what my brother once told me [about
his work with .. hm.. wasn't it Pro-Engineer(?)] to even remember what 'parametric' means in this context.
Ok, I guess I know what parametric means, at least I think in the direction of simply scaling a construction plan
from say model size (e.g. the Queen Mary on 2m model scale) to a full scale construction set according to which this
ship really could be rebuilt. Is that what we are talking about here?
Yes, you are right about Pro|Engineer, FreeCAD aims to be a similar product. Pro|Engineer (Pro|E for short) was the first to introduce the concept of parametric modeling. The traditional modeling way (which is still in use in many CAD packages) is more "basic" and makes use of primitives and boolean operations. It can also use extrusions and revolutions from profiles. But with this method, once the shape is generated, you basically can't modify its dimensions. You need to "hack and slash", if you wanted for example to stretch one side, you'd have to extrude a new shape and fuse it to the first. Modifying a revolved shape can be tedious, you have to add/remove material by boolean operations. Parametric CAD users call these shapes "dumb solids".
What Pro|E brought is a way of keeping track of a shape's parameters through a history tree. For example, you've drawn a profile and revolved it, you can at anytime go back to the original profile and change its dimensions, the resulting revolved shape will get updated automatically.
It goes also further: when in the sketcher environment, you have a set of geometric constraints at your disposal which you can apply to single elements or groups of elements. Such constraints as vertical, horizontal, parallel, concentric, equal, etc. You can of course add dimensions, and those can be equations. So drawing 2D elements in this way requires a new way of thinking: you don't need to draw with precision, since you'll define your profile with constraints and dimensions after it's drawn.
You can check out the Sketcher workbench in FreeCAD, but it's not complete at the moment, it's more like a technology preview. There are two interesting videos showcasing the Sketcher on this blog.
FreeCAD's goal is to be fully parametric, but since it's still in development, some tools are already parametric, and some aren't.
At the moment, primitives such as box, sphere, cylinder and torus are parametric. At anytime you can change their parameters (dimensions). Some draft tools are parametric too: rectangle, circle for example. So if you extrude or revolve them, you can change their dimensions and the solid shape will update. But the multiline tool that I suggested to you is not parametric.
I think what I wrote previously should answer to that. The extrude and revolution features will be parametric if you've used 2D tools that are parametric. But for the extrusion, even if you can't change its profile, you can always change its length; and for the revolve, you can always change the revolution angle (from 0 to 360 degrees).What is exactly the reason that we have lost this property when using extrusion?
(does this apply to revolved objects as well? Would assume so - without knowing the exact reason...
Maybe because FreeCAD doesn't know how to apply scaling parameters to initially used wire profiles used for
the extruded/revolved objects? Hm... if so... that sounds as if it were a -maybe only current- limitation to FreeCAD,
but prior to uneducated guessing I'll better wait for an answer regarding that point...)
After writing my previous post, I played some more with the placement tool and encountered the same problem as you. Werner said he'd take a look, so this should be resolved at some time.Yes, I used the Placement Menue as well.
But my problem was: I made up my angle iron in the wrong orientation...
Yeah, the forum doesn't accept PNG, which is annoying but since it's hosted on SourceForge, I'm pretty sure Jürgens (the project owner) doesn't have control on that.Ok, the PNG-file I wanted to upload has been refused ('invalid image file').
I'm ashamed to admit that I don't remember this. I haven't visited it in a couple decades I think!Quebec ?
wasn't it the nightly facade of the Hotel du Parlement where they had these nice video installations about Canada ?
I loved it!
Regards