Tips for sketchup/3d printing

[earthwormjim]

I gave up and started from scratch,after not being able to find anything wrong with a couple of wheel designs.
Rebuilding from scratch,trying to keep shapes as simple as possible,seems to have helped.
It is a real pain to spend hours,only to find that it is not recognised correctly!!
I have a sketchup model of my inner push fit
hub,just the centre,if it is any good to you...
http://sketchup.google.com/3dwarehouse/ ... 9fe7b13c84
Cheers Jim.

[peterwaller]

I have downloaded meshlab and loaded the exported .dae file into it and it looks perfect just as it does in sketchup.
I then exported it into .stl format and uploaded it into shapeways. It appears that the conversion is in inches so the file was rejected because I said it was in mm and a 0.94 mm dia wheel was too small.
I then uploaded it in inches and it looks the same as the .dae file with an apparent blockage in the centre of the hole when viewed on shapeways.
When I view it on sketchup if I turn the wheel I can see the axis line through the hole in the middle of the wheel so there is definitly nothing there at that stage.
I have just got you centre thanks Jim I might try and incorporate it into a wheel.
Can you give me a link to your wheel on shapeways so I can see if it looks ok on my machine.

[earthwormjim]

There are definateley some issues with shapeways recognising some of my files.
I am sure there are good reasons for it,I am just not sure what those reasons are yet.
Here is a good wheel on shapeways...
http://www.shapeways.com/model/309561/f ... tml?gid=ug
And here is a bad wheel,it is the same wheel,but with a 45 degree slant to the outer hub face...
http://www.shapeways.com/model/309801/f ... tml?gid=ug
It looks ok from the back,but if you spin it round,the front is just a blank circle.
cheers Jim.

[peterwaller]

Even using your hub Jim it still looked wrong on Shapeways.
I have now simplified the wheel design so it has one flat side and the hub and rim are all in one direction and it looks fine on shapeways.
This seems consistant in that I have drawn 24mm and 30mm wheels and both look good so I have ordered some to see if they actually work.

[peterwaller]

The wheels arrived today not bad 7 Days total.
They look really good apart from not being round but a 24 sided polygon which is hardly going to matter once the tyres are fitted.
I was sure I had read somewhere that the steps were just how it was displayed in sketchup but I have now found how you set it.
First you draw the circle then type capital S and the number of segments you want and it then remembers that value until the end of the session.
The centre is a good fit on the motor shaft and they are really light.
1 gm for the 24mm diam and 1.2 gms for the 30 mm diam.
This lot came to about £20:

[earthwormjim]

Mine came in yesterday...

I made my centre hole 2.8mm,as I thought it would be a nice tight fit,but they are too small,I have had to ream them out a bit.
I found that 1mm thick walls with no lip are a bit flimsy.But a lip to the edge of the wheel makes them very rigid,much better...

And they are fantastically light.

[Rhys]

Jim, bit of a tip for you, if you're printing a pair of wheels, you might want to put them both in the same .dae file, this is because there's a $1.50 start-up charge for each model. So if you print the same wheel twice, you''l be paying an extra $1.50. If you print four of them, you'll be paying an extra $4.50.

Also, you might want to make your designs purchasable by you only. At the moment, they're open to the public, and you might see a lot of people turning up at the next AWS with similar wheel to you

[earthwormjim]

Good point,thanks alot.I will do that.

I don't mind if people buy the wheels.
As long as they don't sue me when they realise that the hubs are too small to fit on the shafts!!
Hopefully by revision3 or 4,I may get the holes the right size.

[earthwormjim]

I have been having a go at re designing Raouls chassis.

Loving this sketchup stuff now.
I am using a trackball,does anyone else use a trackball??
I have been using one for about a year. I have just ordered a mouse from ebay,though.As I am wasting alot of time zooming in and out to get accurate measurements.I have bought a programmable button mouse,so in theory I should be able to pan/zoom/shift etc without having to stop every time!!!
I think I will get the chassis made,just to see if the thicknesses/bracing are sufficient.
I am really enjoying playing with sketchup.I always found it a daunting prospect.It is really interesting stuff though!

[Rhys]

Oh god!

You got very good, very quickly! How thick are those walls? To be fair it looks like it'll be pretty tough whatever the thickness. The only thing I'd suggest is maybe making the armour mounts (I'm assuming that's what the 4 holes in the corner are) a fair bit thicker, about as thick as your motor mounts.

As for mouse use, you should be able to rotate and zoom with a standard 3 button mouse. The scroll-wheel zooms in and out, holding the middle button allows rotation.