Is SolidWorks really a solid modeler?

So it is macro-able and hence a candidate for a solid feature ala
polygons in the sketcher?

I am having a hard time figuring out how you did it with only two
extrudes. Guess I'll have to go to CS301 to find out.

 

I didn't do it with JUST two extrudes - that was Dale.
I did two solid extrudes and two delete faces - Dale did an extrude solid
then an extrude cut.

 

Just to be sure we are talking about the same thing:

http://mathworld.wolfram.com/Dodecahedron.html

 

yup.. thetas it. just say the word and I'll send you the model

 

Boy, I must be missing something. Send it please.

 

Ed and/or Dale,
Could you please publicly post your models so the rest of us mortals
could be enlightened?

 

A DRAFT!!!! Duh. And this whole time I was trying straight extrudes.

 

Ed showed me what he did. And he is entitled to another box of donuts.
OOOO I can put it up on my site (with appropriate attributions) if it
is OK with Ed.

 

See below,

I agree that 3D sketcher needs equal relations. But I was able to make the
tetrahedron in a 3D skecth without equal relations. Mate points to planes.

The focus IS on the end user. Its just that they are for the majority of end
users. When they made the first (fill-in-blank with any high tech thing, a
car, a computer, a calculator, etc) did all these devices have all the
functionality when they came out as a new product? Of course not! My first
calculator only could add, subtract, multiply and divide. But that fit a
large percentage of people that first bought them. Then as they went along,
more features were added to suite the majority of what endusers needed or
wanted.

The same is with SolidWorks. I'll bet you that there are few enhancement
requests for dodo creators...

Dan

 

Whoa Dan, I'm not trying to bash, I'm trying to stretch, I'm trying to get
to fundamentals; things that will benefit all users. The title of the
thread may be a bit provacative, but I use the word solid with a very
special meaning refering to regular solids (or platonic solids). And that
question came up because I was reading a book on Computer Aided Graphics
written in a decidely CAD neutral viewpoint.

One thing I found that was very neat about Ed Eaton's construction was that
with the same two features you can get to an icosahedron. Now that is cool.
I suspect Dale's construction can do the same thing. I'd sure like to see
what you came up with too. So far there are three approaches:

1. Two (or more) intersecting extrudes.
a. Stable and quick
b. Requires some knowledge of geometry and constructions.
2. Mated planar surfaces (seems to cause SW problems.)
a. Assy. needs to deal better with overconstrained mates
b. Seems to be some stability problems that need addressing.
3. 3D Sketcher (with a lot of hoops to jump through.)
a. 3D sketcher needs an equal relation
b. 3D sketcher needs a coplanar relation

Now I guess I would qualify as an end user since I sit in front of a tube
doing SW, Nastran, Cosmos for more hours in the day than I care to think
about. And then I'm crazy enough to want to teach the same subject in the
evening. But I think we need a bill of rights to protect the minority end
users from the majority some times. comp.cad.solidworks is the next best
thing to that.

I think the Dodo is an apt illustration. God created the Dodo for a good
reason and the majority helped the Dodo evolve to extinction. See:

http://www.amnh.org/exhibitions/expeditions/treasure_fossil/Treasures/Dodo/dodo.html?dinos

Who knows, the Dodo might have been a more efficient protein factory than
chickens or rabbits.

 

Its fine by me. Give proper credit to Dale Dunn, though... he figured out
how to do it in two features (my first crack at it had four)

 

LOL!

At least you have a sense of humor!

Dan

 

Dale,

I tried it as you described and it worked great! One base extrude and one
cut extrude. thanks, keep up the good work...

Dan

 

Hi Dale,

Using your method, I made a Icosahedrons,

http://mathworld.wolfram.com/Icosahedron.html

but it took me three base extrudes and one cut extrusion. I had to play
around with the angles until they netted the equal length edges. Making a 3"
edge length:

52.62263180deg draft for first pyramid shape extrusion (upward direction)

2.55195242in in between upper pentagon and lower pentagon.

10.81231698deg draft between upper and lower pentagon (downward extrusion)

Can you make this in less steps?

Thanks,

Dan

 

Uhhh...The geeks know this. N = 1 which is what Platonic
relationships are all about.

Bo

 

5 in 3 dimensions, 6 in 4 and I think 3 in all the rest.

 

Dan,

You can do the icosahedron in two if you don't count the plane to
sketch the second extrude on since you can extrude in two directions
from each extrude feature.

And not for something completely different, remove the vertex figures*
from both the dodecahedron and the icosahedron. Voila, you get the
same solid in both cases.

Vertex figure:
On each face of the solid put in a split line between midpoints of the
edges. Once you have done all, use delete face to remove the faces
adjacent to the vertex and insert a plane surface in the hole.

 

That question was answered in a September 25th post. For your
edification follow this link:

http://mathworld.wolfram.com/PlatonicSolid.html

 

Guess you will have to look them up.

Proofs prove that something is true or not true based on assumptions
that probably can or can't be proved. Your why ends there.