Science method

# CAD-Modeling - Science method

Explore the latest questions and answers in CAD-Modeling, and find CAD-Modeling experts.

Questions related to CAD-Modeling

I might have in my design on CST some overlaps but I couldn't find where it is , so is there any way to know exactly where is it? my design waveguide and metamaterial

Are its faces polytopes?

Is there any information in the literature on the geometry and topology of saddle polyhedra?

Can we use them to construct structural triply periodic minimal surfaces?

An attempt to answer some of these questions in:

Dear commubity,

I have a question concernig the geometrical modeling. My question is as follows:

May i create my geometry in ANSYS Design modeler and save it as a CAD model, and then import it in the ANSYS APDL as any CAD file which is imported from a CAD software like Autocad, Solidworks, Catia?

Thank you in advance.

Sincerly,

Hajar

I have a solid CAD model geometry (complex shape). I want to generate random spherical pores within that geometry with desired porosity and pores size.

Instead of SI units, I would like to use millimetres. How can I achieve this with pythonocc?

I am doing some simulation for stiffness identification of ABB irb 7600/500kg serial robot links. The CAD model provided in the ABB library is a solid model, but the actual robot is a shell model. Can anyone help to identify the shell model of the ABB irb 7600 robot?

Hi

I wrote the codes blow for a minimal surface as a part of gyroid, but after running them, I got some errors. Could you possibly explain either what I should do in order to correct them or how I can convert a surface created in MATLAB to iges CAD model?

______________________

This is the link of iges MATLAB codes:

______________________

These are the written codes:

[x, y, z] = meshgrid (-pi/2:pi/32:pi/2); % 3D coordinates defined by x, y, z

v = sin(x).*cos(y)+sin(y).*cos(z)+sin(z).*cos(x); %gyroid formula

figure(1);

fv=isosurface (x, y, z, v, 0);

hold on;

figure(1);

igesout(fv,'gyroid.iges');

______________________

and these are two errors:

Reference to non-existent field 'knots'.

Error in igesout>getEntities (line 256)

if iscell(obj{i}.knots)

Error in igesout (line 91)

[obj,Entity,Num] = getEntities(obj);

usually we use CAD softwares to design a specific part then we convert it to STL to be able to 3D print it using any of the additive manufacturing techniques. I want to know if there is a smart simple way to convert a STL file into one of the CAD forms (step, parasolid .. etc.) so I can modify it (say using solidworks or so) or perform numerical simulations using Abaqus or the same.

I would like to create 3D models from CT/MR image data sets to be used in FEM software (COMSOL). Does anyone have experience with Materialise Mimics and Simpleware ScanIP? Which one is best in terms of being user-friendly and generating smooth CAD models for FEM numerical modeling (electric field and temperature)?

Thank you

Dear all,

I have a Abaqus script that repeats a lattice structure in two dimension. I am modeling lattice cells as solids with their wall thickness. And geometry is a plate-like structure with a smaller out of plane thickness compared to other lengths.

However, i want to roll this structure into a tube like geometry. The result I'm trying to achieve is actually a tube with lattice walls. I want to write this Abaqus script parametrically in terms of mesh repetitions and relative density.

If anyone has any ideas on how to do this and can help I'd be very happy.

We need to capture the 3 D image of a body part and get a CAD model of it. Which we want to analyze for application in a specific domain.

Kindly help

If you want to answer privately. Then you can mail me at kohli.anirudh03@gmail.com

I am trying to make simplified human cell CAD model. It will have plasma membrane, viscoelastic fluids within, nuclear membrane, nucleolus and fluid within nucleus.

Problem is, the plasma membrane and nuclear membrane are very thin approx. 10-20 nm. I don't find any cad software to model this. can you please suggest how to do that.

Hi

I have generated a STL file of a skull using 3D slicer. I would like to convert my STL file into a cad model, so I could split it up into smaller pieces so that it can be printed piece by piece. My initial attempt was using Geomagic Design X where I had imported the STL file. However it seemed as if the skull was too organic/complex for the software.

Does anyone know how I can convert the STL file into a CAD model, or maybe another technique as to split the slit in parts?

Thanks for your help

for a project I want to create a 3D CAD model of the child's chest.

Hello,

I would like to extract all the walls from complex .DWG files that comes from the conversion from a .PDF by AutoDWG software. In these big multi-floor plans, there are multiple types of walls (exterior, office, corridors, etc) that have their own thickness and interior composition (trusts, insulation, etc.) and it's not even always clear to the eye where one type of wall ends and another starts. To give you an idea of the problem, here are two examples of very small regions of these kind of plans.

Note that I'm NOT interested in starting from a high resolution image of a scanned floor plan as the information is already vectorial in the DWG file. Also, I must do it by programming and as little user intervention as possible as this must be part of a bigger software solution.

I would be glad if anybody could propose software, libraries or papers describing methods to extract wall information from such a .DWG file. I guess OpenDWG seems to be part of the solution but if someone has more first hand experience with this problem, I would like to know about that!

some of the researches carried on porous media by using the ultra CT-scan method. they have been scanned in an actual porous metal form, and using some binary conversion methods, the scanned image converted into a 3D model. if anyone has a link for that sort of 3D model please comment below.

thank you

How to define quarter-point element at the crack front, in a Static Structural analysis with a 3D CAD model in Ansys Workbench? Is there an APDL command that can be used in WB do to so?

I would like to learn drawing or getting centerline of a surface in Solidworks. I search on internet but I found limited information. I found a programs like VMTKLab.There is a section for centerline computing.

Ex: http://www.vmtk.org/index.html - computing centerlines.

Probably there is a method to get by using Solidworks.I will work on 3D modelled human leg, I want to get centerline of it to use in analysis as reference. Any ideas? Thanks.

To my limited understanding, FEA gives me part deformation under certain boundary conditions. So if I have the CAD model, I will know how much it will bend (for example) if I press my finger on it , or simply due to earth's gravity.

Now if I only know the shape of a part under gravity (and boundary conditions about how it is supported), can I find out the part shape in zero-gravity space? Is there a way to solve this kind of problem?

Can anyone help me find the find the Pelvis CAD model or Sawbone model with Peprosky type 3A or 3B defect.

Hall scan data can consist of point clouds, (3D) images and videos...

I'm curious if you know about any projects or ongoing research in this area.

The aim of the object detection could be the creation of a map or a CAD model.

Thanks in advance! :)

I'm researching the use of PMI data in a MBD model for use in manufacturing.

I wasn't able to find any information about how threads (e.g. M10) and the ISO system of Limits and Fits (e.g. 20 H5) are handled within STEP AP242. In most CAD systems these are handled very well within the 3D annotations of the native model but once you export them to STEP AP242 you lose a lot of information. This limits the automated use of PMI data when exchanging this data. So I'm wondering whether I'm missing something or whether this is lacking within the STEP AP242 definition or the way it is implemented.

Any help to help me understand this is very much appreciated.

I plan to use V-REP together with python for the development of trajectories in 3D CAD models, the path I will trace on the CAD file and generate a DXF file of it, Python would process it to enter the trajectory in V-REP.

Would someone recommend me any resources to learn how to program V-REP? Or how could I link between the DXF file, Python and V-REP?

For get length and number of crack increase in the crack propagation problem.

I am currently working as a supervisor on a project related to Automotive Aerodynamics. My students are suppose to make a CAD model of a passenger vehicle. The geometry for the CAD model is obtained by taking the blueprints of the vehicle. Then in the next step there will be CFD Aerodynamic analysis and optimization of the vehicle shape ( in some areas) .

So my question is that after doing research work is it possible to be published or it is necessary to take consent of the automotive manufacturer for we used their vehicle as a test vehicle. Kindly give your answers on this issue.

Actually for a project of FEA class, I need to perform FEA analysis for braces application. Please guide from where could I get the CT scans files. Because CT scan files can be converted to CAD model.

My question is, in principle, quite simple. I have the necessity to extrapolate the geometry from a mesh I'm using in Fluent. As a consequence, the extension of the mesh file is .msh (I should also be having the OpenFoam version of the same case). Is there any way I can extract the geometry into, i.e., stl, obj, 3ds, svg (and so on..) formats that I can later open in Blender for rendering? I tried using ICEM, without succeeding. Does FLUENT or ANSYS allow doing such an operation?

How to do simulation in PMC to get mass fraction of hydrogen from Biomass combustion using FLUENT or CFX with cad model of combustor??

Is there any specif papers available.. help me

I am running a sliding mesh simulation for a wind turbine in a nozzle (i.e. a ducted turbine), but at the moment I am having the problem that my solution just blows up after a few time steps - continuity and some of the other residuals diverge and become exceedingly large. I have been running my simulation in ANSYS Fluent, but I do my CAD modeling in SolidWorks the import it over. This method worked fine for the other sliding mesh work I did.

I tried reducing my time step, and that seemed to help get to a later time, but I'm still seeing some significant instability eventually. I heard there was some way to improve the mesh matching between my rotating section and the stable section that would help fix the problem, but I haven't been able to track down how to do that.

Does anyone have advice on getting better connection between a rotating mesh and a stationary one? It seemed like it was a common problem when I was searching online, but I wasn't finding a solution to it. I'm still trying to make adjustments to get the system to work properly.

I opened it in assembly design and then in DMUoptimizer saved it as model and reopened it but couldnt paste its copy in part design ;I faced this error:'"paste is not possible""

The artery models are not patient specific CT models, rather, CAD models based on previous knowledge of human body.

I am currently working with Solidworks.

Solidworks s good for modeling assembly parts but it isn't strong with mechanical analysis.

I worked with ANSYS and Abaqus but both of them are difficult for modeling and running for analysis. I am looking for software that is suitable for enclosure that is easy to run for analysis.

Which one is most suitable software (Solidworks Cosmosmotion vs Adams-MSC) for analysis & motion simulation of mobile robot platform mainly focus on obstacle negotiation??

I am well-versed with Solidworks CAD modeling software so kindly advise me about Solidworks Cosmosmotion for dynamic simulation and analysis of mobile robot platform (multi-body) .

Dear all,

In order to simulate CAD model in MATLAB, I need to using this code. If anyone has the MATLAB code in this regard please share it to me.

Regards.

Hello Everyone,

Can someone suggest me how can i create tetrakaidecahedron model in ansys design modeler or ansys space claim? I have attached the image file below. The model is composed of 6 squares and 8 hexagonal faces and it is closed cell aluminium foam. Please help me to design this CAD model in either ansys design modeler or in ansys space claim. I am looking forward for your suggestions. Thanks in advance.

Kind Regards,

Karthikkumar

Hello, everyone!

I need a software that could pack the arbitrary shaped particles (random packing).

Particle models are prepared in CAD software (see figure for example). Now I need to fill the column (cylinder) with them.

The software is highly preferrable to be free, maybe even open-source.

I heard about Blender could pack spheres, and how about user-defined particles?

Please, advice.

I need to export GD&T information from a CAD model into STEP 242. I tried to do that using SOLIDWORKS and Creo, but saving the design as a STEP file 242 means the GD&T information will be lost even if they have been added as annotations in Creo. However, I read a solution that suggest the use of Constraint Tolerance Feature (CTF) graph files. I could not find a reference that explains what is exactly the CTF file? and how can I generate it?

I will be more than thankful if anyone can help me to understand how can I generate this file by giving me an example.

Rocket mass is changing due to burning of the propellant and this means that moment of inertia is changing too. Moment of inertia is mass X radius of gyration squared. I currently have a simulink model that caters for the varying mass of the engine and rocket. However, I am still having difficulties in determining the changing moment of inertia. I already have the moment of inertia of the rocket without the propellant using my CAD model. Questions are

1.Is there a mathematical formula of determining moment of inertia of the solid propellant?

2. Is radius of gyration constant or it keeps changing? (Assumption is that rocket body axes originate from the center of gravity which coincides with the center of mass)

Sorry my question is long but I would like to hear your views and answers. Thank you

Hello,

In a new project I'm about to start in the garment design industry, I will need to extract some surfaces from the scanned body of a person in order to customize parametrized pieces of clothing based on these surface measurements.

I already used Rhino on another manufacturing project. All its algorithms can be called from Python scripts and reusing its visualization, object creation, geometric algorithms was a big time saver. The problems I encountered were the following:

- Non standard Python 2.7 version (Iron Python) not compatible with lots of recent libraries (difficult to use NumPy, SciPy, etc).

- Non robust mesh algorithms (intersections, boolean operations, etc.)

I would like to get advices from people using other CAD like CATIA, SolidWorks, Pro-E, etc about the ease with which one can extend and customize these software to serve as "frameworks" for custom applications. Which language can be used? Can it call standard C/C++ code or Python code? Are they offering advanced and robust algorithms on triangular meshes?

Thanks

I am trying to get the simulated data for Mechanical properties of (Stress/strain/ fatigue failure) a CAD speciment made of Nitinol (Nickel titanium alloy) after & before cryogenic treatment.

Hello, for my final year project i'm required to produce a finite element analysis on abaqus of the human knee joint. Im starting off by producing an FEA on a simplified CAD model but unfortunately ive been receiving the following error: "Time increment required is less than the minimum specified" and "Too many increments needed to complete the step" after decreasing the minimum increment size.

I would really appreciate if someone could help me get over this problem. I've attached my CAE file.

Thank you

Hi all,

Please suggest me different CAD tools available for MEMS that will allow me to integrate other devices with MEMS (device description is based on differential equations) to study the system behaviour as a whole.

Regards,

Raghu

Hi all,

I want to model the following in Abaqus (just the reinforcement for the rubber hose) : (See figure 1)

I want to do this in order to identify the value of the force at the contact region of the thread knots. (See figure 2)

These are very thin, membrane like structures made of Aramid. They will expand with the rubber hose under internal pressure. I would want to identify the force at the contact under tension/ expansion of the hose.

I am confused as to what is the best way to model these

**thread**reinforcement structures. I would think that**Rhino3D**is a good option since it uses NURBS. I have a fairly good knowledge of Rhino.However, I do not know what properties (section/ contact interaction) to give these reinforcements in Abaqus.

I need DICOM format of femoral shaft fracture to convert them into CAD model. i need them for my research.

Could you please tell me that how one can plot the deformed CAD model in Isogeometric analysis after getting the displacement of x and y dofs of each control points.

Litrature directs that, post-processing in IGA is similar to finite elemenet analysis. I tried to do so but facing the problem while plotting the deformed shape of an objet (e.g. beam of plate). GeoPDE utilizes the Paraview to get the deformed shape. Isn't there a conventional way to do so as we do in finite element analysis.

Thanks

currently some colleagues and I have been working on these issues and the curious thing is that we do not find articles or works that are not more than 10 years, it is as if the enthusiasm for this subject would have died.

thanks for any help.

Hi,

Does anyone know about any website where I can purchase human CAD model which has the option of movable limbs?

Thanks.

Design of composite materials is crusial for material engineers. Accordingly, I would like to utilize the capability of some softwares as autodesk to simulate the compoisites parameters under various conditions of work.

I am importing an .iges file in ANSYS workbench. After importing beam tool is not highlighting. What is the solution for this? please help.

Hello. I just finished my degree and Im thinking of embarking on Masters but im perplexed on a topic and need help. Does anyone have any suggestion on research topic based on my interests below:

"Augmented reality in teaching and learning models"

"Effectiveness of augmented reality in 3D CAD models"

There are more but cant seem to figure which is ideal for me. I enjoyed using the occulus rift during my final year game exhibition thereon Ive picked interest.

I'd be grateful for any form of help to begin.

Thank you in advance

our research group want to focus on 3D Bioprinted scaffolds, hence i want to know regarding commercially available 3D printers.

like PROs and CONs of following printers

1. BioBots

2. Regenova

3. NovoGen

4. Fabion

5. RoKitINVIVO

Hi

I'm running a 3d bioprinter which runs via air pressure. Presently all control of air pressure is manual via a valve set in between the printer and the wall. The printer itself actually also has a valve, where you can set the pressure for the individual print heads. I can change the speed at which the printer prints but using g-code, but would also like to be able to do this for the air pressure. There is, in fact, an M-code dedicated to changing pressure, though I've never seen it used for normal 3d printers. Is there an electronic actuator/valve I can buy which is controlled via the computer?

This is a question to colleagues who ever developed CAD modeling algorithms on B-Rep. Examples are Boolean Operations, fillets, Euler operators, etc. All such algorithms are quite complex in nature, and I wonder if there are any "conventional" tools which a researcher could use to ease his life while holding CAD-neutral position (e.g. not being sticked to Catia, whatever). I have heard about Djinn and the idea looks pretty good to me. Though, I don't know if it has found a real use in academia. To be more specific, let's say I want to implement feature suppression algorithm, e.g. defeaturing of fillet chains. I can start with OpenCascade as a kernel, but it does not offer a convenient SDK for visual profiling of my algorithms. I will want to see the intermediate results of Euler ops., to check curvatures at surface points, to query neighbor faces, to check their surfaces, and many other things which are quite tedious without a good tool at hand. Is there any SDK like this?

To put it short, if I am about to start my own geometric kernel, which tools should I have in my tool box?

Thanks.

I'm in possession of an FDM 3D Printer (Robo R1+) and just came across the Taulman Nylon 680 which is FDA certified. I also have a stainless steel nozzle for printing the parts.

My question is: Do I need to take any further steps to be able to defensibly use 3D printed parts for product contact?

For 3D Printing by which software we can design ? Pro-E Or Solidworks ?

I am doing in cylinder flow analysis of piston bowl.

Hello,

I'm working on a commercial product where I need to estimate the 6DOF pose of a known 3D CAD (closed 2-manifold triangular mesh) in a single 2D image (see attached picture).

In general, this a difficult problem but under our operational conditions, we can impose the following constraints simplifying the problem:

- The CAD object is known and we do NOT aim for generality like recognizing the class of all chairs.
- We could get the user to position the camera approximately to a specific pose (distance from the object, general orientation +/-15deg, etc.)
- If possible, we would use only the edges of the image (like Canny) to find and match against the object viewed from a given position.
- This would be used in an industrial environment with manmade objects (pipes, valves, junctions, etc) without much texture.

All these constraints lead me to think that even relatively old and somewhat basic techniques could work. For example, in the Sonka and al. book (see link below), section 12.3.2 Goad's algorithm explains a 1986 paper from Goad C. "Fast 3D model-based vision" which could work relatively well under our assumptions with its top-down "hypothesize-and-verify" approach.

I also know that the industrial vision and robotics community have tackled this problem and its generalization for a long time so there is bound to be something usable out there.

My question is the following: Would somebody know of a commercially usable implementation (like OpenCV, etc.) solving this problem? More specifically:

- I'm NOT looking for deep learning stuff needing an offline learning phase with thousands of viewpoints from our CAD models.
- I'm NOT looking for RGB-D techniques relying on depth sensors. The color is also irrelevant as the CAD is colorless.
- "Old" techniques out of research fashion are OK, even preferred as we will be running on a low performance computer.
- Ideally, using C or C++ (may depend on OpenCV for example).
- Usable commercially (licensed under BSD, MIT, BOOST, etc.), not GPL.

Thanks in advance for any leads anybody could offer.

Bruno

Suppose I take a pole (hollow, length>>width) and convert the CAD model into a surface model specifying a certain thickness and mesh it in a commercial CAE package such as ANSYS (in this case it'll be a

**surface mesh-quad**)Compare the results of the above analysis, with a similar ribbed model (not surface, solid) and do

**3D meshing-hexa, tetra**Will the results be in 99.999% conformity?

I have coordinate information of irregular shapes in excel file, the irregular shapes are within a rectangular plate and origin of coordinate system lying on one corner of rectangle. There are around 20 such irregular shape. I need to generate part drawing of the system so that I will be able to mesh the part and perform FEA. What are the possible ways to do it and which software to use??

Thanks in advance.

I have tested the SolidWorks Flow Simulation package. It is quite handy to use with CAD models and results seems very nice, but I haven't been able to find theoretical background on it. I mean, it must be some version of Navier-Stokes equations, but which version, what approximations it uses?

Moreover, the turbulence parameters "intensity" and "length", any knowledge about their theoretical background? My guess is the "length" refers either to Kolmogorov length or Taylor microscale, but would like to know more about it.

Hi all,

I'm trying actually to improve my method of recognizing from STEP file of CAD models, manufacturing features using rule-based and entity growing approaches. Anyone interested to chare ideas?

hello, I want to simulate a vehicle in fluent , I have the cad model of my car with it's actual dimensions. generating the vehicle mesh is very Time-consuming for my computer system , so can I scale my model in smaller dimensions and then achieve true results as well as actual dimensions ?

This book contains Feature Based Manufacturing.

Which I am unable to find in other CAM related books.

Hello!

CST studio offers many voxel models, CAD models that are voxelized when imported, and only one full-usable CAD model. CAD models have smooth components with continuous shapes, whereas voxel models are conformed by cubes with limited spacial resolutions (around 1mm x 1mm x 1mm per cube).

I'm wondering if the resolution of the voxel models is good enough for simulating the performance of small implantable devices (on the order of a few voxel cubes), or if a CAD model is always more adequate at any frequency band (without considering the meshing part still).

Thank you.

2012, ASTM accepted a standard format called Additive Manufacturing Format (AMF), capable of storing color, materials, lattices, and constellations , unlike STL format contain only surface mesh information of CAD model. I see that AMF fits nicely for the needs of additive manufacturing for gradient component or multi-material fabrications and is better than STL. But, I don't know why this format is not widely accepted.

could someone provide me a 3D CAD model of right ventricle?

I want to simulate the blood flow into the right ventricle and then investigate the effect of omentum layer on the behavior of ventricle and blood flow.

Thank you

suggest any solution so that CAD model imported to abaqus software

How we can determine the control points and knot vectors required to represent the geometry of a structural member such as a square plate, a circular plate etc .

I’m looking for an approach to reconstruct a 3D model of eye glasses (without lenses) in a fast and accurate way with as little as possible manual post-processing (as in no Meshlab if possible!).

One difficulty for laser, structured light or traditional photogrammetric approaches is the diversity of the material (from highly specular metal to very diffuse black plastic), the impossibility to apply powder (could not resell the product afterward), the geometrically thin structures without texture, etc. I also want to capture the texture of the glasses to have a good rendering of “the real thing”.

One aspect of this particular problem that might help is the very constrained geometry/topology of eye glasses. Is this something that could be exploited by some kind of synthesis image-to-CAD algorithm that could use the information contained in a few images to

*generate*a faithful 3D model?Thanks

So, the matter is that I've modeled a system that deals with 9 transmission lines in Power System Computer Aid (PSCAD) Program.

but, when I put Multi-meters between two sides of transmission lines the calculated

**P,Q**and**V**differs from each other far behind the desired amounts comparing between putting a Wire between the buses instead.I've tried PI and Overhead Transmission lines(Bergeron Model & Frequency dependent) but no differences.

The Question is that What should I do in order of getting the same values before and after the transmission lines.

Thanks a lot.

I have a model that created by multi surfaces in Catia software. but, i want to make one surface by using multi surfaces.

who can advise me ?

We can ask a very similar question about when the industry moved from drawing boards and typewriters to the first CAD and word processing systems in the 1980s. The answer is everyone made money because the work processes became more efficient and accurate. If you made a mistake you could undo it. If you had to draw the same window 100 times, each copy was exactly the same as the first. If you wanted to find a particular word or phrase within a 100 page document, you could search for it in seconds.

Now it is time for the industry to move to the next stage of technology and structured data.

The designer will no longer spend time retyping the data from a 2D CAD model into Microsoft Excel to produce a 200 instance door schedule, and they will not spend time going through a 150 page specification looking for each place they have requested the contractor to submit proposals or samples. The contractor will no longer be informed about clashes in the design by the structural and M&E engineers on site during construction, and they will be able to more efficiently price projects by getting more competitive prices when purchasing in bulk, with less waste. And finally, the building owner will be able to manage and alter their facility using an accurate digital model of the physical building.

Please show models for which extracting correct mid-surface (midsurface, medial) is difficult? Situations for which mid-surface shows gaps, overlaps etc.

I have a cad model of a bone and a patient-specific guide attached to it in stl file. (Imagine an object clip on top of another object but not rigidly attached to it).

-- How can I import the model as an stl file into MATLAB? -- How can I create a mesh for the cad model?

-- How can I determine their mesh density?

-- How can I use this to determine the stiffness parameters?

--How can I generate the coordinate of the vertices and normals of each triangles of the stl file?