FreeCAD for boat design test

Hi, I've tried FreeCAD these days to create surfaces for hulls, and I have to admit that it has great features.
For now I have created some surfaces starting from models in OBJ format, used for the generation of spline curves from the points generated by the mesh model that I created with Blender.
The tools used are:
The Workbench Mesh Remodel, Workbench Surface, and finally the Curves workbench.
All useful for carrying out the various phases.
I used the Mesh Remodel both to create the stitches from the mesh and the various Spline to generate the surfaces.

Surface has been used for some surfaces such as Curves to generate more complex surfaces such as Gordon from a grid of splines.
FreeCAD has many features to accomplish many task and I've much to understand but I think isn't bad.

Below some screen shot of these experiments.



and this below is a video tutorial for surfaces modelling







Greetings

 

And this is a new attempt just made now with an other hull type. I don't have a full control on the spline but I'm a novice with FreeCAD, I'll improve in next future and I will do a better hull, but for two day of self-learning I'm quite satisfied

 

New hull also with lines plan generated directly in FreeCAD with the section tool of the parts workbench.

 

I'm experimenting with FreeCAD, and I'm really impressed, I didn't think it was possible to make these surfaces.


Today I also found the way to trim a surfaces, and I also saw that the quality is not bad, I opened this model exported in IGES with PolyCAD and Moi3D
Still a lot to learn but I am increasingly convinced that it is a good alternative CAD.
This model is only part of learning path with FreeCAD, has many issues, but is my fault.

Test trimming

FreeCAD model view


Nurbs Surface control with Moi3D and I think they are very good



Soon I make a more complete works but I'm still learning a lot.

 

Ciao PF, thanks for the postings about FreeCAD.
It does seem to be a powerful software, and is very handy as a viewer for many file types.
I am very used to Autodesk interfaces so I get confused in FreeCAD but that is operator error.
Most of my career has been 2D design in another industry, I would really like to learn some 3D workflows better.

 

Hi I'm also a beginner with FreeCAD, but I have experience with this type of software, FreeCAD has a chaotic but not complicated workflow, it's done by many developers and everyone has created things that are not always consistent with each other.


I'm involved right now in drafting some advice on how to generate surfaces starting from 3D mesh objects with FreeCAD, as soon as it is complete I will share it here.

Greetings

 

Surfacing Tips:

Surface creation with the help of a mesh model in OBJ format

Introduction

This is a workflow that simplifies the creation of surfaces with FreeCAD with the help of a 3D model created with Blender to be used as a guide for generating curves using the vertices of the polygons.

With this workflow you can easily draw curves in 3D space without constraining them to planes.

The structure of the mesh if done well can give excellent results in the final result.

I use Blender for convenience to make these models with Subdivision Surfaces, but you can also use other programs that export meshes as an OBJ.

For ease of use I do not apply the subdivision modifier in Blender because it would generate models with too many vertices and it would be very difficult to locate the vertices to generate the B-Spline curves.

I recommend to keep a low number of vertices for the mesh, because these will then be the control vertices of the curves and a rule to always keep in mind because the surfaces will be better and homogeneous.

Export model from Blender

I usually use the default settings of Blender and I never change the measurement units, and these in Blender are in meters; this must be taken into consideration when exporting the model for FreeCAD from Blender, once the 3D object to be used with FreeCAD has been selected, choose Export to OBJ from the file menu.



In this image it is also visible export to IGES, this is an add-on that allows you to export the subdivision surfaces directly in IGES format readable by FreeCAD without any conversion, this component is very useful and simplifies a lot, however this to be used correctly requires a basic understanding of how subdivision surfaces work in Blender and their use with all limits. to download this add-or this is page Digital-Sculptors Export IGES Add-On.

Now in Export dialog set the scale transformation export options from 1 to 1000, and our object will be in from meters to millimeters in FreeCAD, moreover the Blender axes orientation are different and to obtain the model in FreeCAD with the right alignment they must be selected for Forward Y Forward and for Up Z U Below is the image of the export options I use, if you do this regularly you can add this in the Presets on the top pressing the plus icon and whenever necessary you can use your Preset by selecting Operator Presets from the menu.



Now I open FreeCAD and open the OBJ file just exported from Blender.

Then a dialog form will appear and you have to select Alias Mesh (Mesh) and press select



After you have opened the model you need to activate the Workbench Mesh Remodel. , which can be installed from the Tools menu by selecting the Add-on Manger item below and install the Workbench you need for this tutorial.



With the Workbench Mesh Remodel. tool for vertices, generate the vertices from the mesh as shown in the image below with the tool visible under the mouse pointer.



Select the MR_Points object in the Tree view alongside and if you want to change the size of the vertices, I set this value from 4 to 8, useful for selecting the vertices, which is sometimes difficult to do.



Another important thing is to disable the ability to select the mesh during the process of generating curves from these points. there are various possibilities of displaying the mesh and sometimes I use the Display Mode from Shaded to flat lines,this makes it easier to locate points around the mesh.



Now you can start with the generation of the curves through the selected points in order, the curves must be generated with the selection of the vertices always with the same direction and all go in the same direction from the start to the end, if not this can generate surfaces twisted on themselves, when the direction of the generated curves is reversed.



Whenever at least 3 vertices are selected, it is possible to use the command create a Spline from 3 or more vertices and holding down the shift key it is possible to prevent the curve from being closed, therefore shift must always be kept pressed because you need to create the curves useful for generate the patches of surface from the model, If two vertices are selected, you can use the command alongside which to create straight segments.



Once you have generated all the necessary curves for the surfaces you can hide the objects you no longer need in the view.

Here I have also made the curves on the opposite side but it is enough only to make one half of them and then with the Workbench Part use the mirror command.



Most of the surfaces can be built with the Surface Workbench., but some more complex ones need to use the Curve Workbench which can be downloaded and installed with the additional components manager as done before for the Workbench Mesh Remodel

Here I have used the Gordon command in the Curves Workbench to create this curved surface which is constrained by a grid of straight lines, this is a very useful command for generating curved surfaces based on a grid.

Here the FreeCAD window is reduced to have smaller images to insert in the document and it is not possible to see all the icons that are hidden.



And here the Gordon surface obtained from the BSpline grid created earlier, I would say that it is a good result and it was all in all simple



With the Curves Workbench I have made all the more complex surfaces now I can move on to the Workbench Surfaces, which is complete and can often be used to do everything.



The Workbench surface must have the curves always in the right direction and must be selected in order for the generation of the surfaces, and has an interface with the management of the options.

When the command from the menu is selected, you can go to the Dialog Box and add the curves, however I recommend viewing the documentation of both Workbenches available by clicking on the following links. Surface Workbench. and for Curves Workbench.

Before changing the Workbench I need a curve divided from those generated for the surfaces I do not create a half curve because I only have two vertices in the bow half and I need a curved line to do this the Curves Workbench has some useful tools to manipulate and create curves and works similar to the Workbench Mesh Remodel but has some differences I recommend you explore these tools.

This command in this case is convenient because it divides the selected curve in two and for me this is excellent and allows me to have tangent curvatures.



Here is the split curve that I can use to generate the top of this model with a new surface. I hid the previously generated surfaces for convenience because it simplifies the selection of the necessary curves for the surfaces creation.



Now I activate the Surface Workbench for the rest of the missing surfaces.

With this Workbench you must first select the command to use and in this case I will use the command for the surfaces, from the edges, and then in the dialog box I select the add button and then I will select the lines in sequence.



This is the Dialog box



Here is the surface generated by the 4 edges at the top, one of which is part of the previous division



In this case I can create the other surfaces with this command but for straight parts you can use the command a to create surfaces from sections useful for creating lofted parts even from only two curves. this command also has the same workflow as the previous one

And this is the result of this process that makes things simple with surfaces.

You can create a compound from the generated surfaces and then you can export them to IGES so that you can use them with other CAD programs such as PolyCAD, Rhinoceros or continue with FreeCAD to create the rest.





Naturally this process is only an indication on how to start in a practical way with FreeCAD, some surfaces must surely be rebuilt to eliminate errors, in fact from what I have done for now it is not possible to obtain a perfect solid, I have to rebuild the curves and the surfaces in a different way.

With FreeCAD it is possible to draw curves directly and obtain probably better results

 

Here an other experiment done now.
The images in the first two images are made by surfacing a mesh OBJ generated with FreeShip, the image 3 and 4 , are the Imported IGES, generated with FreeShip from subdivision surfaces. FreeCAD Gordon surfaces are two, and IGES exported from Freeship have 4 surfaces.

FreeCAD hull surfaced over mesh OBJ



and these the two images are the IGES exported with FreeShip and imported in FreeCAD



This is an other test useful on checking the overall dimensions, by making surfaces on mesh created with Blender used as a guide for the B-Splines.
With B-Spline created in FreeCAD over the 3D mesh objects, it is possible to have a good precision, with this method, the circles and curves created with Blender's polygons are inscribed inside FreeCAD B-Spline, and this allow to have same dimensions.

 

I'm really pleased to see Freecad continuing to progress. I found it helpful to use the environment mapping feature to illustrate curved shapes in a way that my brain could make sense of them.I haven't yet tried hull surfacing, but I have been watching several of the Mango Jelly tutorials on youtube and they are very helpful. I also agree with the comments regarding workflow and interfaces, very little is intuitive but the features are in there somewhere or other.This thread provides a good illustration in that a lot of the work is done with the Curves workbench and not with the Surfaces workbench and it seems strange when creating surfaces. The orphaned workbenches are another source of frustration, they have seen no development for a long time and some have hardly seen development since they were begun.It seems to be a very good package that is really close to being a single universal solution to many design challenges. How many other packages can offer design,analysis and even machining from a single file and at no cost?

 

Hi, I decided to make some effort to understand the Curves Workbench better, and I finally drew the b-splines and I also understood how to move with the constraints and snaps. it's very simple hull but I'm thrilled with the result. I am highly satisfied.

 

IGES imported in Moi3D below also attached the hull in IGES, and is completely drawn with FreeCAD.

 

Here a new attempt with FreeCAD after few day of using it, and now I done a better rowing boat only with FreeCAD a Whitehall 14ft the IGES exported from FreeCAD is attached below

 

You really ought to put a link to this thread on the Freecad forum; people would find it inspiring. https://forum.freecadweb.org/

 

I did the final test, with surfaces and b-spline curves and after this object made with surfaces and joined in a perfect solid with FreeCAD you can do everything
.

 

I'm increasing my knowledge of FreeCAD every time. A simple boat by William Garden, the Island Tender, with many surfaces, splines, trimmed surfaces and solids, and some personalized colors