Export from AutoCAD to STL

[theodore.tsesmelis]

Hi guys, first of all I would like to say that I am totally new to autocad. I have the two attached .dwg files of a indoor room (same room with small changes in each .dwg file) which they provide the wireframe of the room. Now I would like to make these wireframes solid and save them as .stl files, which then I would like to load in matlab so that to get the x,y,z points and create a kind of point cloud. The problem that I am facing now is that for some reason I cannot export them as .stl files because it is complaining that is not solid or something like that, then I tried to make them solid with the ways that you are describing in this thread but without success, therefore I would appreciate if someone could help me with that. Thanks. 

[john.vellek]

Hi @theodore.tsesmelis,

I see that you are visiting as a new member to the AutoCAD forum. Welcome to the Autodesk Community!

I am looking at your LAB file and see that it is made up of primarily 3Dfaces and blocks. I am not sure where the furniture blocks came from but you might isolate each one and verify that they can be exported to STL.

I suggest that you also isolate objects. For instance, put your walls on a wall layer, your ceiling on a ceiling layer, your floor on a floor layer. This will help you move around and work in your model.

I suggest also, before you insert components into your space, that you consider building the room and verify that an export to STL gives you what you are trying to achieve.

Please select the Accept as Solution button if my post solves your issue or answers your question.

[theodore.tsesmelis]

Hi @john.vellek,

Thank you for your reply. The two scenes are imported from the Relux software and the ReluxCAD addon and then saved as .dwg files. If you notice there are already three different layers, one for the structure (i.e. walls, ceiling, floor, etc...), one for the geometry (i.e. chairs, tables, cupboards, etc...) and one for the luminaires. So I would say that it is already split in different components. Moreover, if I switch to the 3D modeling view I can see that I can provide a solid view to the objects:

but I do not know the reason that I cannot save it as .stl. Saving it as an .stl file then what I want to achieve is what is described in the following link https://www.mathworks.com/help/pde/ug/create-and-view-3-d-geometry.html where the cad model is loaded in Matlab and then you access each face. When I try to export the file as .stl I am getting the message "Select solids or waterlight meshes" can someone explain me what this actually means and if I can do something with the already existing .dwg files to correct this. Many thanks again.

Best,

Theo

[john.vellek]

HI @theodore.tsesmelis,

I have attached a QUICK version of what I am describing. You will see that the walls were drawn and then PRESSPULLed or EXTRUDEd which results in true 3D solids. Similarly the floor and ceiling were created in the same fashion.  This is different than a collection of faces which is what your original file contains.

I didn't spend a lot of time on this as when checking accuracy of heights and thicknesses of walls, for instance, it appears there are some errors.

I suspect that the furniture contained in your original might also be faces or some sort of meshes which might not be watertight to export to a STL format.

Please select the Accept as Solution button if my post solves your issue or answers your question.

[theodore.tsesmelis]

I see, thank you for the example. However, do you know if there is any other option to create the 3D solids or watertight meshes from the existing group of faces and meshes other that recreating the whole scene again in Autocad, since this will save me a lot of time. As I said I am not that familiar with Autocad, therefore I would have to start from scratch something that I would like to avoid for just a simple action.

Thanks.

Best,

Theo

[john.vellek]

Hi @theodore.tsesmelis,

You could certainly try to convert the faces to surfaces using CONVTOSURFACE but I am guessing that by the time you do this, give them thicknesses and then try to use UNION, you are likely going to have some holes so the model will not be watertight.  This means it will not export to STL.

I grabbed some dimensions off your model and (rounding to whole numbers) created a new plan. I used polylines which I then could Presspull or Extrude to the right heights. After this I used UNION and SUBTRACT to create the basic lab model.  I tested an STLOUT and it worked fine.

The next step will be to figure out what to do with the furniture. I tried to STLOUT and it rejects those blocks. The tables should be simple to construct but the chairs will definitely be trickier. Where did you get the blocks? Perhaps there are some other formats that we can explore.

Please select the Accept as Solution button if my post solves your issue or answers your question.

[theodore.tsesmelis]

Hi @john.vellek,

Many thanks for your time creating the new .dwg file of the lab. I will try your suggestion about using CONVTOSURFACE and UNION though I am not sure how but I search about it. All the included furniture were added from the Relux embedded libraries. I was able to extract them as .blk files but I do not know if in this format can make of any help or not, please find them attached though the ones in the initial .dwg files are a bit of modified on the fly in order to meet some size requirements. In general the whole thing is too much complicated therefore for that reason I would prefer if there was any straight forward solution but it seems that there is not.

Many thanks again :-).

Best,

Theo

[john.vellek]

Hi @theodore.tsesmelis,

I apologize but I thought I provided links in my prior post. I have added them now.

I took a look at the furniture and I think it would be quite a task to convert them to watertight objects. Unfortunately, the blk files won't work in AutoCAD.

Perhaps you will find some suitable content at BIMOBJECTS.com

[theodore.tsesmelis]

Hi @john.vellek,

Thanks again for your response. You mentioned that creating the tables, the cupboards and the separating panels in the first file should be easy, I was thinking that in this case I might skip the chairs, so that at least to have something functional. What do you think, would that be easily doable?

Thanks.

Best,

Theo

[john.vellek]

Hi @theodore.tsesmelis,

Looking at all the furniture blocks in the file, they are going to be hard to clean up.  There are so many filleted edges that it will take a while. I am wondering if you really need that level of detail for what you are making.

So, I made a new cabinet block that consists of 3 simple 3D boxes that I UNIOINed. Then I made another 3D box for the door, applied a handle from a curved profile I applied to an arced path. Lastly I made a center panel for the door using another 3D Box.

I suggest that you can create a simple table using similar methods. Create a table top using a 3D box. Create the side aprons (the rails under the top using a rectangle swept along a rectangular path or from 4 3D boxes.  Legs can be made using simple 3D cylinders.

I would try to grab some chairs from BIMOBJECTS.com or from some manufacturer sitees such as Steelcase, Haworth, Herman Miller, Knoll, etc.

Please select the Accept as Solution button if my post solves your issue or answers your question.

[theodore.tsesmelis · Accepted solution]

Hi @john.vellek,

We had some progress :-), I followed the instructions in the following link https://knowledge.autodesk.com/support/autocad/troubleshooting/caas/sfdcarticles/sfdcarticles/AutoCA... where it is suggesting that if nothing works in autocad then to try to load the file in 3ds max and try to export it as an .stl from there since as it is explicitly saying "3Ds Max is well-known to manage meshes and 3D Solids". Then I said ok lets give it a try, and it worked :-). I managed to load it in matlab and I am able to see the faces, etc... using the script from here https://www.mathworks.com/matlabcentral/fileexchange/3642-cad2matdemo-m I am putting all the links so that if someome faces the same problem in the future to follow the links ;-). You just need to remember to save the model from 3ds max as an ascii .stl file and not a binary one.

In any case @john.vellek, I am really thankful for your time and your help. Thanks a lot again.

Best,

Theo

p.s. To answer your question about having such detailed meshes I need that because I will try to simulate the radiosity light modeling inside this room. Therefore, I will need even to make more patches from where I will calculate the form factors of the geometry of this scene.