Adventures in 3D printing Sketchup models

xiombarg

Sending off a model to i.materialise today. Let's see how it works out! I was up literally all night, when I sleep I'll be dreaming in quads!

Quick question. For price comparison I'm also sending model to shapeways. It has to be in STL format and I'm using meshlab to export. So I'm exporting as Collada, importing into meshlab and exporting STL.

Problem is, my model is coming out tiny, significantly smaller than it should be. Any ideas what I'm doing wrong?

[edit] found a STL plugin which works fine, still can't think why the other method didn't though, even though I specified model units.

When you upload the file on their site are you specifying metric or SAE? And then what units... good chance this is the problem.

olishea

Thanks for the reply....but did you see my edit?

I got it working by using a "Export to STL mm" plugin. Does exactly what it says on the tin.

When uploading I just specify mm and it works fine. I double checked the volume with my sketchup model and it's exactly the same. I have sent off for some CNC quotes too and the STL file I used was fine, preview looks good and the volume was the same. Just a shame CNC is crazy expensive!

xiombarg

@olishea said:

Thanks for the reply....but did you see my edit?

I got it working by using a "Export to STL mm" plugin. Does exactly what it says on the tin.

When uploading I just specify mm and it works fine. I double checked the volume with my sketchup model and it's exactly the same. I have sent off for some CNC quotes too and the STL file I used was fine, preview looks good and the volume was the same. Just a shame CNC is crazy expensive!

Oops, I didn't notice the edit.
For cnc try getting a quote from http://www.ponoko.com
They used to have good pricing, though I haven't worked with them for a couple of years.

olishea

That's great thanks. Just putting some quotes together. Got some CNC quotes from UK but it was £421 for only a small item, less than 100 centimetre cubed.

CNC milled Aluminium is £421 whereas 3D printed Alumide is £84.73 although not directly comparable materials. Brass is also slightly cheaper when printed. Although I don't the think quality of either will touch CNC finish.

The beauty with 3D printing is that it makes you think outside the box to remove material and save money. Well that's the plan lol

olishea

Would you need an internal support structure to print the attached models? Have you guys seen mesh mixer?

d12dozr

@olishea said:

That's great thanks. Just putting some quotes together. Got some CNC quotes from UK but it was £421 for only a small item, less than 100 centimetre cubed.

CNC milled Aluminium is £421 whereas 3D printed Alumide is £84.73 although not directly comparable materials. Brass is also slightly cheaper when printed. Although I don't the think quality of either will touch CNC finish.

The beauty with 3D printing is that it makes you think outside the box to remove material and save money. Well that's the plan lol

Oli, for the CNC'd parts, did you optimize the model for the process? ...or did you just get a quote for the same model that you used for 3D printing? I'm guessing the cost may be significantly less if you can save them repositioning time.

@olishea said:

Would you need an internal support structure to print the attached models?

Depends on how you're printing it. For any industrial process(like i.materialise or Shapeways uses), you don't need to think about supports. For printing on a small desktop machine, you would need additional supports.

I've only used meshmixer for converting files...pretty sweet what you're doing with it!

olishea

I used meshlab not mesh mixer to create those (with immense difficulty!)....but i was just wondering what you thought of mesh mixer. I saw some videos and was blown away, especially the hollowing out a shell feature.

@unknownuser said:

Oli, for the CNC'd parts, did you optimize the model for the process? ...or did you just get a quote for the same model that you used for 3D printing? I'm guessing the cost may be significantly less if you can save them repositioning time.

No I just sent them the stl file.

How do I go about this? Any links?

d12dozr

D'oh, I meant to type Meshlab, but meshmixer popped out Meshlab is the one I use for converting files - works great for that. I've used Meshmixer for building support structures for my desktop printer, and for light editing of STL files. It handles sculpting pretty well. I haven't used it to full potential (I like my Sketchup ), but has some very handy features beyond Skectchup's capability.

Re: optimizing for CNC, I would chat with the customer support at your CNC provider to see if there is any way that changing the geometry (without changing your design intent) would bring the cost down. This link briefly explains what I mean.

olishea

Thanks, they are cool shapes but incredibly difficult to model, each one takes a few hours. Yeah meshlab looks awesome, will be a great tool for shelling things.

I'll chat with CNC company and see what they say. I doubt I can reduce the cost by 8 times!! If they were £50 in aluminium, then maybe, but not £420! They didn't even give me a stainless quote because I know it will be crazy! Oh and i know the above models can not be manufactured by CNC, before anyone tells me. They were just for 3D printing.

olishea

Does anyone know how to export sketchup quads as actual quads when exporting obj

Or is there a file type that actually maintains quads?

Any quad mesh I make, whether it be in sketchup or wings turns out triangulated in meshlab. I've tried stl and obj import and they both have triangles. hmmmm.....

xiombarg

I'm stretching my memory here, but I know that some programs like Maya require modeling in quads (for clean results) BUT then when rendering it triangulates everything as the finished product, which leads me to think that triangulation is usually the case(?).

Maybe Autodesk 123D or Blender? Both are free and might be worth a shot. The 123D interface is similar to Autocad, which is old school and archaic and sucks in my opinion. But I'm just wondering if other programs have exporters that even though they export to the same file types still might keep things in quads once exported?

xiombarg

@olishea said:

I used meshlab not mesh mixer to create those (with immense difficulty!)....but i was just wondering what you thought of mesh mixer. I saw some videos and was blown away, especially the hollowing out a shell feature.

@unknownuser said:

Oli, for the CNC'd parts, did you optimize the model for the process? ...or did you just get a quote for the same model that you used for 3D printing? I'm guessing the cost may be significantly less if you can save them repositioning time.

No I just sent them the stl file.

How do I go about this? Any links?

There are CNC service sites (like Ponoko) that give details on how to optimize. Sorry I don't have links off hand, but do a search and I'm sure you will get a lot of results.

olishea

Thanks again. I don't want this thread to descend into troubleshooting, so I have posted my other questions in another thread. I got a reply off the CNC company about optimisation, gonna have a phone call with them tomorrow, but they are more than willing to help get this project off the ground and show how to reduce manufacture cost. Fingers crossed!