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@@alejandroalonso2216 hello. I am glad you found the tutorial usefull. Probably you reduced the mesh size too much in meshlab or the mesh was not cleaned.

@@haithamshawwa8573 what type of project?

Hello. In the OBJ equation multiply or divide "X" , "Y" ,"Z" by 2 and try. That is ine way to have 8 gyroids... The best way is still to generate one and in an STL manipulation software xombine them. Like meshlab.

And parameterize in STL software too?

@@joerees9060 parametrize in Matlab and then use STL pattern option either in meshlab or better in CAD form in FreeCAD

Been working on this for a little while. Followed your process but have been trying to upload the file into NX Siemens to work on it more. When I upload into NX, each element appears to be its own body.. any suggestion on how to make it one solid body? Is this something I’m messing up in freeCAD

@@joerees9060 Replace the section where the main equation is written with this: % Gyroid equation OBJ = cos(X/2*SFact).* sin(Y/2*SFact) + cos(Y/2*SFact).* sin(Z/2*SFact)... + cos(Z/2*SFact).* sin(X/2*SFact)+(0); Change Def = 80; (Improves mesh quality) Try it. You will get multiple gyroids.

Hello, 1- you should switch the boundary limits and the volumes you combine at the end of the code. It is doable, if you break down the code and the functions in it. 2-The thickness can always be controlled by the T parameters.

@@RamiRouhana hey really appreciate the quick reply! Just that I am not very good at MATLAB. I fear if I break down the code I’ll end up actually breaking it.

@@kanav1998 just experiment woth the code at the end that combines the surfaces. Keep an oroginal backup of the script. Understanding better the code will allow you to manipulate it easier.

I tested on 2024b , it appears to work. Place the STL write code in the same folder where the script is.

1-What aeesmbly do you mean ?? 2- save as 'SAT" file type

@@RamiRouhana I want to assembly two different TPMS structures but when I insert this in FreeCAD software I am not able to select any face of the structures to mate 2 faces

@@RamiRouhana .sat file option is not available in freecad save types

@@SubhaNath-m5u try IGS and STP

@@RamiRouhana thank you sir.

FreeCAD 0.18

Hello, I currently have v2020.07

Hello. In the comments i posted the equation to calculate volume and the reference paper. I will add that to the video description.

I show these steps in this video. Using FreeCAD , or you could use Fusion 360 or there is an abaqus plugin "STL to solid". Watch until the end.

Hello. I am glad you found the vid useful. The paper reference DOI is also in another comment. I can only assume that the equation holds until t=1.38

Hello. Adjust the mesh density, but also check the other comments. I provided some solutions.

Yes there are methods if you export node coordiates you can make what is called SPH in Abaqus. Or you can adjust the script in matlab to generate a sphere at the location of nodes, there are tutorials of that.

Thanks for your reply please can you explain more, I'm a beginner in Matlab.

@@relab5346 It is not an easy task in matlab. It is better if you import the CAD to abaqus. Look for tutorials to convert the CAD to particles SPH in abaqus. For matlab , this might help arxiv.org/abs/2209.05189

Try to adjust the mesh density you generate in matlab , your mesh might have defects in it. As mentioned in the video, the step in Meshlab for mesh optimization is very helpful, and in some cases necessary.

@@RamiRouhana I input "40" mesh density in matlab. And I optimized faces into 50000 faces in Meshlab. However I got this error....TT

@@신상오원자력공학과한 have you adjusted the t value or are u following the exact same steps in the vid. I would say try Fusion360 to convert mesh to CAD . Maybe the new FreeCAD has a code problem.

Hello. The equation of a gyroid is equal to a constant. By reducing or increasong the constant, the gyroid surface shifts like an offset but in 3D. So offsetting equally give a symmetric thick shell .

@@RamiRouhana Thank you. Sir And I have one more problem in FreeCAD I followed your order well but when I do this function Part - Convert to Solid There is a error msg : because Shape is not a shell I don't know why.... I really created shape from mesh first but I can't make a solid from shape

@@신상오원자력공학과한 you have to click on the part name on the left sidebar before you do the conversion.

In your code i made some modifications for get that cylinder, with booleans operations, but the result is a little bit bad, because the surface of the units cells are stranges, so i dont know how i can solve that. % Clear all previous commands clear all close all clc % Variables you can change SizeL = 1; %average length of RVE Def = 60; %definition % Variables you shouldn´t change SFact = (SizeL/2)/pi; %size factor of RVE A = 10*SFact*pi; %lowest and max coordinates of meshgrid D = A/Def; %definition factor % Generation of gyroids [X,Y,Z] = meshgrid(-A:D:A); %creates mesh grid % Gyroid equation OBJ = cos(X/SFact).* sin(Y/SFact) + cos(Y/SFact).* sin(Z/SFact)... + cos(Z/SFact).* sin(X/SFact); T = (-0.05*(X.*X + Y.*Y) + 1.25); OBJ = OBJ >= 0 ; % Extrusion ExtrusionHeight = 10 CylinderRadius = 5 extrusionMask = Z <= ExtrusionHeight; % Cylindrical shape cylinderMask = X.^2 + Y.^2 > CylinderRadius^2; cylindricalShape = cylinderMask & extrusionMask; % Combine gyroid structure with extrusion and cylindrical shape ResultSurface = OBJ | cylinderMask; % Isosurface and isocap [F1, V1] = isosurface(X, Y, Z, ResultSurface, 0); [F2, V2] = isocaps(X, Y, Z, ResultSurface, 0, 'below'); % Combine isosurface and isocaps into one F3 = [F1; F2 + length(V1(:, 1))]; V3 = [V1; V2]; % Visualization figure; P = patch('Vertices', V3, 'Faces', F3, 'FaceColor', 'blue', 'EdgeColor', 'none'); view(3); camlight; % STL export of the entire structure % Change current file path with desired file path. % Visualization axis equal;

@@camilomaturana9011 You are welcome. What is the code you added ?

@@RamiRouhana This parts (The code is up): A = 10*SFact*pi; %lowest and max coordinates of meshgrid (This for make an a repetition of the unit cells in the space) OBJ = OBJ >= 0 ; % Extrusion ExtrusionHeight = 10 CylinderRadius = 5 extrusionMask = Z <= ExtrusionHeight; % Cylindrical shape cylinderMask = X.^2 + Y.^2 > CylinderRadius^2; cylindricalShape = cylinderMask & extrusionMask; % Combine gyroid structure with extrusion and cylindrical shape ResultSurface = OBJ | cylinderMask; % Isosurface and isocap [F1, V1] = isosurface(X, Y, Z, ResultSurface, 0); [F2, V2] = isocaps(X, Y, Z, ResultSurface, 0, 'below');

You are welcome.

The volume it is possible by the equation in the video description. Surface area should be possible but I do it on meshlab.

​@@RamiRouhana Thanks for your reply. Is F3 representative of the surface area of the gyroid, and is V3 the corresponding volume? Is there a direct relationship between the T value and the thickness of the sheet gyroid?

From your previous comment - These two equations give you a sheet gyroid. To find approximate thickness : sin 0 cos 0 + sin 0 cos z + sin z cos0 =+0.1 sin 0 cos 0 + sin 0 cos z + sin z cos0 =-0.1 Solving these 2 equations we get z= arcsin(t) & z= arcsin(-t). so arcsin(t) should be the thickness of the sheet gyroid, right?

The thickness is not a constant, this is the value you get near the center of the cube face. The deviation becomes larger with larger T values.@@SyedArafunNabi

F is the faces , and V are the vertices. @@SyedArafunNabi

this was very unique . I got lucky ,went straight to the airport after that for my flight back to Germany. I will not be sharing the video there.... :p If you ever make a video of the next show , please share here.

With this script it would be easier to make on cell and make the repition using the generated STL on another software like meshlab. You could do it by adjusting the paremeters in direction x to compress 10 cells in and then later stretch it but the mesh will not be very homogenous. You could also try to define a larger volume for X direction, but I have not myself tried that.

👍🏻🙏

I am sorry. I cannot help you at the momet with a specific coding task. You will need to export surface node coordinates and write a script to compare positions (In/Out).

Actually I want to apply load on one face and fixed in other end in matlab.

@@SubhaNath-m5u I explain mesh conversion on FreeCAD at the end of the video.

Thank you sir for your guidance. I am looking that is their any way we can convert this to solid in matlab itself? @@RamiRouhana

I totally agree. That is why i recommend making a CAD as shell and simulating. If that passes the test then infil is a bonus.

Hello , that is possible. Try to run the script with "Def = 40" changed to "Def = 80" . That defines the mesh density.

​@@RamiRouhana Thank you for your answer! I mean unit cell is a repeated structure of the gyroid structure. So, I want to know if I can make a structure that has many smaller repeated structures. Sorry for confusing you.

@@いーま-v5j That would be possible in the script but very tricky, you will need to adjust the the values in the cos(x) to cos (x/3) and then increase resolution. You will get 3 cells in the x direction.

Hello , try checking mesh quality on meshlab and check if there are holes or bad mesh. Often there are duplicate surfaces or independent nodes.

@@RamiRouhana Do you know if meshlab changed some of their settings? I could not find compact faces and vertices in their submenus so I went straight for removing and merging.

@@jonathanvillada9330 there should be other software for mesh correction. Meshmixer maybe.

Hello , that is possible. Try to run the script with "Def = 40" changed to "Def = 80" . That defines the mesh density.

Thank you! Ich wünsche Ihnen viel Erfolg bei Ihrem Studium!

That same question was asked below. I added the equation and the reference paper.

Hello Yusuf, the best software would be Abaqus. Check the tutorials . If you do not have access to the software you can try Fusion 360.

it could be that you are using a mesh sensity that is low. Try first to run the code as it is and see if the STL is generated. If it works and then give errors due to the changes you made, then the changes you have made are causing the error.

@@RamiRouhana The STL is not generated even with your original file. How do I increast the mesh sinsity?

@@OfufualuaguAugustus you need to instal the stl generation plugin in the right folder.

I have done it yes. You can export the other geometry by tweaking the combine code at the end.

@@RamiRouhana % Clear all previous commands clear all close all clc % Variables you can change Sizex = 1; %average length of RVE Sizey = 1; Sizez = 1; Def = 60; %definition % Variables you shouldn´t change SFactx = (Sizex/2)/pi; %size factor of RVE SFacty = (Sizey/2)/pi; SFactz = (Sizez/2)/pi; A = SFactx*pi; %lowest and max coordinates of meshgrid B = SFacty*pi; C = SFactz*pi; Dx = A/Def;%definition factor Dy = B/Def; Dz = C/Def; % Generation of gyroids [X,Y,Z] = meshgrid(-A:Dx:A, -B:Dy:B, -C:Dz:C); %creates mesh grid % Gyroid equation OBJ =(A*B*C)-(cos(X/SFactx).* sin(Y/SFacty) + cos(Y/SFacty).* sin(Z/SFactz)... + cos(Z/SFactz).* sin(X/SFactx)+(0)); OBJ1=(cos(X/SFactx).* sin(Y/SFacty) + cos(Y/SFacty).* sin(Z/SFactz)... + cos(Z/SFactz).* sin(X/SFactx)+(0)); T = 0.5; OBJ =(OBJ-T); OBJ1=(OBJ1-T); % Isosurface and isocap [F1,V1] = isosurface(X,Y,Z,OBJ,0); [F2,V2] = isocaps(X,Y,Z,OBJ,0,'below'); [F4,V4] = isosurface(X,Y,Z,OBJ1,0); [F5,V5] = isocaps(X,Y,Z,OBJ1,0,'below'); %Combines isosurface and isocaps into one F3 = [F1;F2+length(V1(:,1))]; V3 = [V1;V2]; F6 = [F4;F5+length(V4(:,1))]; V6 = [V1;V4]; % Visualization P = patch('Vertices',V3,'Faces',F3,'FaceColor', ... 'magenta','EdgeColor','none'); view(3) camlight P = patch('Vertices',V6,'Faces',F6,'FaceColor', ... 'green','EdgeColor','none'); view(3) camlight %Visualization axis equal here is the code...i want to represent both the gyroid's and its complement inside the cube but with different colors...The graph is a little strange. Do you have any idea why?

I am sorry, I cannot help you with that.

@@RamiRouhana I just want to know which part of the code to delete so the gyroïd does not become a smooth uniform surface

@@OfufualuaguAugustus Try commenting out the isosurface section.

@@RamiRouhana But if i delete that isosurface line it will impact the "combine" and "visualisation" parts.

1-What do you mean by unit? 2- create the stl and copy in a row using fusion software.

Sir unit means I need 20 cm length gyroid

@@subhanath6405 you can scae up the stl to any size you need after genrating it. Use fusion software or Meshlab.

I am glad this video is helpful. 1-The wall tickness if the sheet gyroid is not constant. You can estimate it by setting X and Y to 0 in the equation and calculate for Z value for the constant set to +t and -t. Example : sinx cosy + sin y cos z + sin z cos x = +0.1 sinx cosy + sin y cos z + sin z cos x = -0.1 These two equations give you a sheet gyroid. To find approximate thickness : sin 0 cos 0 + sin 0 cos z + sin z cos0 =+0.1 sin 0 cos 0 + sin 0 cos z + sin z cos0 =-0.1 Solve for Z and calculate the difference, you will have the sheet thickness in Z. It would be better to do the same for X and then also for Y. The smallest value it the closest to to average. 2-This paper will help you with your questions. journals.sagepub.com/doi/10.1177/0278364920907697

The volume fraction of the sheet-like structure can be controlled by its thickness that is constant throughout the structure and depends on the values chosen for the constant . The relationship between the level set constant and the volume fraction of the solid-network Gyroid reinforcement phase is as follows: Vf = 0.65c

@@RamiRouhana thank you sir for this information

In the code, this is the Gyroid equation. % Gyroid equation OBJ = cos(X/SFact).* sin(Y/SFact) + cos(Y/SFact).* sin(Z/SFact)... + cos(Z/SFact).* sin(X/SFact)+(0); The Diamond Equation is : sin(X/SFact).* sin(Y/SFact).* sin(Z/SFact) + sin(X/SFact).* cos(Y/SFact).* cos(Z/SFact)+ cos(X/SFact).* sin(Y/SFact).* cos(Z/SFact)+ cos(X/SFact).* cos(Y/SFact) .* sin(Z/SFact) - (0); replace it in the code.

You are welcome Max! Share this video with those who might be interested and let me know If I can further help or what additional video could be useful.

I hope you find it helpful.

Hello Alexandre. For printing you do not need to do any changes to the exported STL file. The slicer for printing fills the volume based on you print settings, number of walls and infil precentage if you are using FDM. If you are using SLM or SLA or SLS additive technology the STL model is assumed a solid in the slicer.

Hello. When the error occurs it indicates usually the line of code where the error is. The forums suggest it is an error related to stlwrite yes. Make sure you install the plugin using Matlab add-ons. It could be dependent on the matlab version you are using also.

@@RamiRouhana oh, I looked at the video carefully again, You've already explained it thank you so much. I solved the problem :)