3D Printing

[jmhanby]

I am trying to 3D print a model.  I found the scale feature in modify however certain objects will not scale down such as windows and doors.  I tried ungrouping the objects and that worked for the stairs but not the windows and doors.  Has anyone had luck in 3D printing a model?  Got and tips to share?

[mac@stairworks]

What if you export the model as a parasolid, import the parasolid in a new file, scale it and export as .stl file?

[jmhanby]

We will try this and let you know! 🙂

[Piotr Karczewski]

Hi @jmhanby,

I'm exporting vectorworks models to .stl files and it works pretty well. The only thing which is not ok is printing imported .stl files with complex mesh objects like screws.

 

[Grzegorz Krzemien]

@jmhanby

I'm using Prusa Slicer for prints and if needed, I often scale model directly in the slicer.

My attachment shows a floor from my project, exported as stl without any transformations (so walls are walls, windows are windows etc) and then scaled directly in the slicer. I've had no issues yet.

[Piotr Karczewski]

@Grzegorz Krzemien how lond does it take Your printer to print this kind of file?

 

[VIRTUALENVIRONS]

Hi Piotr,

I have been doing 3D printing recently to help a friend.  I am not sure what he uses to print with, etc.  We use either Step or STL.  For homes or "vector linear"  models, Step works very well.  STL files for more free form models.  

We are not having many problems, but I think this is because I never use the automated tools for building models, (walls and roof, etc). These are great tools for creating design dwgs, but for 3D printing, I think it is best to keep the models as close to the native format as possible.  The only problem we run into sometimes is surface normals get flipped, but I am assuming your software can handle that.

Enclosed are two images, Step for the lighthouse and STL for the gingerbread man.  The Lighthouse was made using the standard 3D tools and the Ginger Bread man with NURBS tools.  The STEP files had problems handling the white frosting.  NOTE: it is possible these issues could be limitations of the printing software.  There is a learning curve.

 

 

 

[Grzegorz Krzemien]

@Piotr Karczewski to print my example it takes almost 3 hours with 0.2mm layer height.

[Piotr Karczewski]

On 2/23/2023 at 6:23 PM, Grzegorz Krzemien said:

@Piotr Karczewski to print my example it takes almost 3 hours with 0.2mm layer height.

That's fast... 50mm/sec or faster?

[FBernardo]

Hi all!

 

We've been playing around with 3D printing some models, we can export correctly to STL using the ASCII option, although how would be the best way to improve the printing of the windows and as the nosel we have is 0.4mm and the mullions and framing is usually a simple dot which then looks terrible or fails!

 

any advice? 

[Claes Lundstrom]

11 hours ago, FBernardo said:

Hi all!

 

We've been playing around with 3D printing some models, we can export correctly to STL using the ASCII option, although how would be the best way to improve the printing of the windows and as the nosel we have is 0.4mm and the mullions and framing is usually a simple dot which then looks terrible or fails!

 

any advice? 

On the file format side, you can also try using OBJ files, which works just as well as STL on my printer driver software Ultimaker Cura. I can't verify it, but I guess it may be possible to print in color using OBJ too if the model has color and textures, and the 3D printer is a color printer.

 

For scale models, you need to make sure not to use thinner elements than the printer can handle. On my (admittedly modest but well working) printer, it seems to be around 1.2 mm but it can of course vary depending of the specifications of the printer. in the example, I had to make a special edition of the model, one for full scale 3D printing (model size 10 meters and skin thickness 6 mm), and one scale model edition, where the skin thickness was set to 1.2 mm. 

[FBernardo]

@Claes LundstromThanks for the help, although what I was looking for is more of how to best prepare the vectorworks model to be exported to 3D print it

 

Like how to try and improve the windows so it doesn't go so slim or even the walls, the software will scale the building properly but the windows will become too thin... I wanted to create a set of rules and settings so I can share with everyone in the office so they can print easily without constantly being present. 

[VIRTUALENVIRONS]

This is so cool.  Short video showing a 3D Basket ball net modelled in Vectorworks and printed in real (fast) time.

 

Couple of things.  Vectorworks shifts surface normals back and forth like a basket ball game.  It seems any tools that modifies the geometry can be a culprit.  This is where C4D is an asset.  The Align surface Normal Command in C4D fixes thousands of reversed surface normals with one command.

 

Regardless the video is slick

 

 

[Claes Lundstrom]

On 3/23/2023 at 6:29 PM, FBernardo said:

@Claes LundstromThanks for the help, although what I was looking for is more of how to best prepare the vectorworks model to be exported to 3D print it

 

Like how to try and improve the windows so it doesn't go so slim or even the walls, the software will scale the building properly but the windows will become too thin... I wanted to create a set of rules and settings so I can share with everyone in the office so they can print easily without constantly being present. 

There are a few basic rules that are useful to follow, assuming that you are using an extruder style printer with a single extruder so that you can't add supporting material that you remove in a step 2: 

 

1/ Make sure that you have enough thickness. On my fairly basic printer, I have found that 1.2 mm always works. In my boat example, the contractor wanted 5-6 mm on the full scale model (about ten meters long). When I scaled it down to fit my printer having a build height of 250 mm, and printed in two parts giving a model height of about 500 mm, the material thickness fell below 1.2 mm, so I had to produce another model with thicker walls relative to the full scale model.

 

2/ For single extruder printing, the rule is to avoid angles exceeding 45 degrees. Imagine building something out of dry sand. If the angle is too steep, it will simply collapse. On my boat example, I had to find a setup that avoided thes 45 degrees. Standing on the transom would not work as it leans outwards 12-14 degrees, which would make the model fall over. Splitting it along the centerline and printing it in two pieces lying on the side would not work as the sides would exceed 45 degrees by a wide margin. The solution was to split the model in the middle. Each part could then stand up without any problem, and I could double the size of the model. The transom and two plate was however a problem, so I printed them as separate parts with joints at an angle to to hide it as much as possible. On a house, you can think it a similar way. How can I for example print a roof having a flatter roof angle than 45 degrees? You simply print it as a separate piece standing up on the side, or for more complex shapes, you can ask yourself if it's possible to split it in the same way as I did with the boat hull, so that you manage the angles and can maintain a shape that stands without falling over. Windows and doors can of course be a problem if you want to print it with see through properties, but you can print a wall lying down instead ?

 

3/ How can I check if a model is a true solid model, and would therefore cause a minimum of problems? The basic criteria simply means that the part or parts all consist of closed shapes. If you still have a problem, you can check if the normals all face outwards. A quick test is to convert a given shape toa mesh and then calculate the volume of it. If you do get a volume, the model is most likely correct. If not check closed shapes and volumes again until it works. 

 

3/ You can of course print a house model as a solid object, having a mesh inside but it does have the disadvantages of just being an exterior and it would also take longer to print. It would therefore probably make sense on very small models representing volumes instead of being models looking like real houses.  Below is an example of a solid print, that is, it's filled inside with a mesh structure.

 

 

[VIRTUALENVIRONS]

Hi Claes,

Beautiful boat, excellent.  Although I only build for a company that does 3D printing, there was as you pointed out a learning curve.  In particular on what a printer can and can't do.  Below is a diagram I found helpful and speaks to your instruction.

 

What method do you use for connecting parts that were made in two parts?  

 

Edited July 12, 2023 by VIRTUALENVIRONS

[Claes Lundstrom]

17 minutes ago, VIRTUALENVIRONS said:

Hi Claes,

Beautiful boat, excellent.  Although I only build for a company that does 3D printing, there was as you pointed out a learning curve.  In particular on what a printer can and can't do.  Below is a diagram I found helpful and speaks to your instruction.

 

What method do you use for connecting parts that were made in two parts?  

 

 

Yes good illustration what I meant.

 

3D printing requires a special mindset designing for 3D printing, where you have to extract a way to work and how to split the model into parts, and finding a good orientation for the print. You just need to practice.

 

I typically glue the parts together, using a glue that can handle the slightly non sticky surface of thes plastics. On very thin skins, like the boat hull above having a thickness of just 1.2 mm, I typically add a small flange along the joint, and of course on the inside, looking a bit like a frame or bulkhead. This adds surface area to the glue joint, but also adds a bigger footprint towards the printer bed, which is useful as it is a skinny shape relative to the mass that moves around above, and therefore risks falling over when the bed moves. 

 

 

[VIRTUALENVIRONS]

I can see for your boat models that glue is the optimal method, as it is with most.  The company I do some work for was lamenting this process for some objects, so I looked at creating a snap together system.  I simply designed a separate snap the would fit into both sides and hold them together. 

The video below shows how it works.  The tower is a combination of glue and snap.

 

Below the video is a cross section of the snap.

 

 

 

[jmcewen]

We used to do something very similar when I was working with CNC routers all the time.  We would make jigsaw-puzzle shaped tabs to lock sheets together when the product was larger than 4'x8'.  Once you figure out your tolerances just save the tabs and slots as a resource and drop them in as needed. I always love problems that can be solved once and kept for the future.