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    • Rahul Ponginan

      Please click here for a short but important announcement   03/26/17

      Dear Users Our Commercial and Academic users around the world can use these same forums here as before i.e. the Altair Support Forum , Commercial users from India with solver queries can go to the Solver Forum for India Commercial Users , Academic Users from India and AOC India Participants are requested to go to the Forum for India Academic Users and AOC India Participants , We will be tending to all queries in all the forums promptly as before, thank you for your understanding. 


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Showing most liked content since 04/23/17 in all areas

  1. 6 likes
    Hi all. i made some hypermesh macros in form of "toolbar" if you feel it interesting, please send me your mcid
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    Dear All, You can refer to attached document which contains Tutorials ( Model Files + Process PDF ) for 1. Hyper Mesh for FE Modelling 2. OptiStruct as solver for a. Analysis b. Optimization 3. Radioss as solver for NL Analysis Students can solve these tutorials & can ask their query on the forum itself. AOC_2017_Practise Models.zip
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    Hi, looking for relevant code in scripts folder and find what you need: #open contact manager source [file join [hm_info -appinfo SPECIFIEDPATH hm_scripts_dir] abaqus Contact_wizard CW.tcl] #open autocontact ::autocontact::CWautocontact::AutoContactGui #invoke selecting components>all *createmark comps 1 all set ::autocontact::CWautocontact1::newElems [hm_getmark comps 1] ::AbaqusCW::HighLight off if {$::autocontact::CWautocontact::flag==1} { set ::autocontact::CWautocontact::flag 0 } if {[llength $::autocontact::CWautocontact1::newElems]} { ::autocontact::CWautocontact1::AddCompsToTable } # set proximity distance set ::autocontact::CWautocontact1::proximity_entry 5.0 # invoke "Find" button ::autocontact::CWautocontact::UpdateInterface
  6. 2 likes
    When you have big diffence in element size, it's better to make several transition zones (geometru splitting). By this method, in stead of do 10mm=>2mm, you can do 10mm=>8mm=>5mm=>2mm.
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    "RBE3 with less than 3 legs should not exist " It means for single RBE3 element you should not have less than 3 slave nodes.In your case RBE3 which has two slave nodes is creating problem for run.
  10. 2 likes
    it's mine you can learn learn to create a toolbar here
  11. 2 likes
    Use Load Step browser>> DLOAD>> Gravity>> and select element set to chose a particular rregion or select all elements.,
  12. 2 likes
    Regarding Strain Energy & Strain Energy (Density) here is some more info. The units of energy are force*distance, so when a load is applied and the material deforms, we are putting energy into the material. This energy introduced into the material due to the loading is referred to as “strain energy.” We prefer to normalize strain energy by unit volume, and when we do so, this is referred to as strain energy density. The area under a stress-strain curve is the energy per unit volume (stress*strain has units of force per area such as N/mm2 , which is the same as energy per unit volume N-mm/mm3 . We will be assuming linear elastic material only. Most metals and alloys are linear elastic prior to the onset of plastic deformation, so this is a valid assumption. Though Element Strain Energy is a good measure to watch in Modal analysis, as it gives an idea on the area of concern & to go for the mesh refinement there as ESE in modal analysis is somewhat similar to what Stress in Static analysis. But if we go for Static/Structural analysis then Strain Energy Density could give you an idea on what elements/area of your model are contributing more in taking the load (absorbing). This same factor is used in optimization as well, where the load-paths are identified where the model have high strain energy density. So basically you get idea where you should strengthen your part. High stresses & High strain energy could be on common areas in some cases but not always guaranteed. So better to go for Stress results when your main concern is Stress (which is there in most of the cases). But when your main concern is Stiffness of the structure i.e you want to limit the deflection/displacement happening in your structure then you may want to stiffen your part wherever it is showing high strain energy density. Just to add, Strain Energy Density dependent function is also the main criteria on which Hyperplastic materials are based, as the behavior of Hyperelastic materials can’t be described with a single modulus like we describe for a general elastic-plastic material. Refer below link for ESE. http://www.altairhyperworks.com/hwhelp/Altair/hw14.0/help/hwsolvers/hwsolvers.htm?ese.htm
  13. 2 likes
    Animation files (A**) are independent of output block. As Prakash mentioned ,output block helps you to output set of request (like displacement, reaction forces, etc...) to time history file. A time history plot of the extra history variable can be created using Output Block
  14. 1 like
    Hello that's me again After a fully integration of the tires in my model I managed to make some simulations on road thanks to the .rdf file (flat and polyline roads). Now I would like to create more complicated roads. I saw that we can create 3D roads with Open CRG and I would like to know how can we add this kind of road in the model ? I didn't find specific information about this in the User Guide. Also what is the point of the Road Builder (Vehicle Tools ==> Road Tools) ? Is this where we have to import our CRG model ? Thanks for the replies !
  15. 1 like
    Hi Prashanth, Please input /ANIM/BRICK/BFRAC in the engine file for generating animation files for burn fraction.
  16. 1 like
    @Merula I am going to create an RFE for a similar feature.
  17. 1 like
    Hi Leox, I think you can use solid map for this. First at the end of the 1D elements put 2D elements with dia at the end of the wire and create Solid (hex) elements by using node path option. select beam nodes as node path. After that you can use sureface--> from Geometry option to create geometry in hypermesh.
  18. 1 like
    Hi Andy, This is a know issue with 2017 and our Dev team is working on it. I will check if there is any workaround for this.
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    Generally, value between 0.2 - 0.4 provides good balance between achieving small progression of solution and extra compute time needed to achieve the convergence.
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    Relaxation factor is primarily a number which is used to converge the solution.
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    There are two options for interference fit. First you can simulate the physical press fit process in RADIOSS. Define contact between the two parts, constrain one part and apply an imposed displacement on the other part and simulation the physical press fit process. Second option is to use /INTER/TYPE24 contact and set INACTI=-1 which will apply forces to remove initial intersection caused by the press fit. The one limitation with INACTI=-1 is that it applies the force all at once and for large initial penetrations the force can be too large. To reduce the force you can use the STFAC option on /INTER/TYPE24. In the attached model, STFAC=0.25 seems to give reasonable results. Run the model with STFAC=1 (default) see the difference. I ran the attached model in RADIOSS version 2017.1 but 14.0.230 or 2017.0 should also be fine. Interference_Fit_rad_s2_0000.rad Interference_Fit_rad_s2_0001.rad
  23. 1 like
    Hi Sumit, Can you share the *.hf file or the *.rad file which you have used for running springback ? i can help you further.
  24. 1 like
    He was wrong at 'puts dofl' and 'puts wgh1', the puts command returns nothing
  25. 1 like
    Hey, as help says: *rbe3 mark_id independent_dofs dof_size independent_weights weight_size dependent_node dof weight the last parameter is the weight, which is zero in your case. If you bother, here is my way of creating rbe3: eval *createmark nodes 1 {"by box"} [expr $x-$delta] [expr $y-$delta] [expr $z-$delta] [expr $x+$delta] [expr $y+$delta] [expr $z+$delta] 0 inside 0 0 0 hm_createmark nodes 2 [expr $nodeId] *markdifference nodes 1 nodes 2 set numberOfNodes [hm_marklength node 1] #Arrays set arrI() [lrepeat $numberOfNodes 123] set arrD() [lrepeat $numberOfNodes 1.0] eval *createarray $numberOfNodes $arrI() ; eval *createdoublearray $numberOfNodes $arrD(); eval *rbe3 1 1 $numberOfNodes 1 $numberOfNodes $nodeId 123456 1; Best regards, Merula
  26. 1 like
    The imported CAD looks like it has some faults, which may have contributed to unexpected behaviour. Attached is a version of the file that seems to work fine (although I didn't try to mesh/run anything). I recorded the steps that I took in the Lua file, so you can replay them and see what was done. The version I used was: 14.0.432-293039 (x64) PEC_teile.cfx recorded_script.lua
  27. 1 like
    Hi, For the hollow cylinders you can find the center manually using distance panel (F4), three nodes>>circle center option. Create a seperate component collector for rigids with no card image, no material and no property. From 1D panel, select rigids and in independent node option select the center node and for dependent nodes select multiple nodes option and select the nodes inside the cylinder. Finally, you can go to 1D panel, select masses and select the rigid center node and enter the mass value. The element type will be CONM2 which defines a concentrated mass at a grid point of the structural model. Hope this helps.
  28. 1 like
    Hello Thank you Mr. Rahul for addressing my query.,I was able to locate the file.. Regards Rishabh
  29. 1 like
    Hello, Please find attached video where you can get how to give velocity inflow in AcuSolve. While selecting an option from drop down menu, co-ordinate system (Cartesian, cylindrical and spherical) specifies vector components to be given as an input. This will be very much useful for 3D cases. velocity_inflow.mp4
  30. 1 like
    Hi, You can use MAT8 card in OptiStruct solver.
  31. 1 like
    Hi, just go to the Altair Connect page, and to the Download section: https://connect.altair.com/CP/downloads.html?suite=HyperWorks Then choose DOCUMENTATION and go to the TUTORIAL FILE section. BUT since the tutorials are not yet updated with the Topo-Optimization exercises, I uploded separately the new tutorials in the link below. The link is available for 2 months. https://securefiletransfer.altair.de/link/HpoKa9oYmuRRdMIljEyvhO - JUST TYPE IN YOUR EMAIL TO AUTENTICATE Best Regards
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    Many thank ! I already solved it and got energy absorption value.
  34. 1 like
    Mil, If your interest is to apply on total area then Yes, For example if you want to appy 100Mpa on an area which covers 5 elements then you need to divide pressure for each element. Instead provide a load factor. For example for same 5 elements at t=0 pressure is 5Mpa and at t=2 pressre is 100Mpa So I create a pressure load collector of 1Mpa per element which makes 5Mpa for t=0 and in tabled1 I provide Y=20 scaling the pressure to 100Mpa
  35. 1 like
    Hi, A possible workaround for the same is export (File>Export) the curves in excel format, edit the coordinates of the curves and open the same in HyperGraph.
  36. 1 like
    Thanks for your answers! I solved the issue another way in the end, which didn't include solving my initial Problem mentioned above. Although I think your way would work @Prakash Pagadala. Thanks!
  37. 1 like
    Hi, Have you made a Local coordinate system for the spring and then make the dof update for spring in the same direction of its axis. This should work I think.
  38. 1 like
    If you are using Solid Thinking Inspire for analysis & optimization.Then above screenshot loads shows that load acting on entire face not on single point.Connectors option allows you to use rigid elements (Rigid i.e RBE2 & Flexible i.e RBE3) for load transfer.
  39. 1 like
    See attached video. Its a .swf file, so a browser with Adobe Flash plugin should be able to play it. streamlines_in_FV.swf
  40. 1 like
    I just figured it out. There is a multiplier option that take care of the issue only for visualization. see attached. Thanks, Maysam
  41. 1 like
    @riham1994 Yes, it may happen as you are loosing the tolerance and reducing the accuracy. I will once again check your model and will update to you soon.
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    This article describes the use of symmetry in CADFEKO and explores the benefits in terms of resource requirements by way of an example. Introduction Electric and magnetic symmetry can be used to reduce runtime and memory requirements in FEKO, as discussed below. It is applicable to the MoM and all the hybrid techniques where MoM is involved (such as MoM/PO and MoM/FEM), but cannot be used in conjunction with the MLFMM. Technical Background Electromagnetic field problems can possess three types of planar symmetry: geometric, electric and magnetic. The type of symmetry is defined by the geometric properties of the structure and sources. Geometric Symmetry In this case the geometry of the structure must be symmetric with respect to the symmetry plane, while the sources may be arbitrarily located. Such a setup generally leads to non-symmetric current distributions on the structure. Electric Symmetry In the case of an electric symmetry plane, not only must geometric symmetry hold, but additional requirements also have to be met by the sources. Figure 1 shows these requirements. The electric current density must be anti-symmetric and the magnetic current density symmetric. A physical interpretation of an electric symmetry plane is a plane which can be replaced by a PEC wall without changing the field distribution. The tangential component of the electric field and the normal component of the magnetic field thus disappear at such a plane. Figure 1: Requirements on sources for a plane of electric symmetry. Magnetic Symmetry In the case of a magnetic symmetry plane, geometric symmetry must again hold, again with additional requirements on the sources, but different from the electric case. Figure 2 shows these requirements. The electric current density must be symmetric and the magnetic current density anti-symmetric. A physical interpretation of a magnetic symmetry plane is a plane which can be replaced by a PMC wall without changing the field distribution. The normal component of the electric field and the tangential component of the magnetic field thus disappear at such a plane. Figure 2: Requirements on sources for a plane of magnetic symmetry. Computational Benefits of Utilizing Symmetry in FEKO When using numerical methods to solve electromagnetic field problems, symmetry may be exploited to reduce computational costs in terms of runtime and memory requirements. In FEKO, the three types of symmetry planes discussed above result in the followin benefits: · Geometric symmetry: since the current/field distribution does not generally possess any symmetric properties in this case, the unknown coefficients on the whole mesh must be solved. Therefore no reduction in memory usage is obtained, as the matrix equation being solved is the same as it would have been, had symmetry not been considered. However, a reduction in the computation time for setting up the matrix equation does result. This reduction is achieved by exploiting the fact that the interaction between any two basis functions is the same as that between their symmetrical counterparts. · Electric symmetry: as with geometric symmetry, less computational time is required to calculate the matrix equation entries. However, the major additional benefit is that the number of unknown coefficients is reduced by a factor of roughly two. Thus the system of linear equations to be solved has dimension of half of what it would have been, had symmetry not been considered. The impact for the MoM is a reduction by a factor four (=2*2) in memory requirement, as the MoM has fully populated matrices. The impact for the FEM is a reduction by a factor two in memory requirement, as the FEM leads to sparsely populated matrices. The reduction in unknowns also leads to dramatic lowering of matrix equation solution time. · Magnetic symmetry: the same benefits result as in the case of electric symmetry. Clearly, the benefits of symmetry can be significant. Usage in CADFEKO In CADFEKO symmetry is considered a property of the model. Symmetry planes are defined via the Define symmetry planes dialog under Model in the main menu (see Figure 3). The coordinate planes x = 0 (yz plane), y = 0 (zx plane) and z = 0 (xy plane) may be defined as planes of symmetry (geometric, electric or magnetic). There is no restriction on assigning symmetry properties to more than one of the coordinate planes, in which case the computational benefits are compounded. CADFEKO indicates the current symmetry of the model in the 3D view, as shown in Figure 3. A preview is always shown while the Symmetry planes dialog is open. The display of symmetry planes may be deactivated by toggling the Show symmetry planes icon. The symmetry display is coloured according to the symmetry type (green for geometric symmetry, orange for electric symmetry and grey for magnetic symmetry). Figure 3: Symmetry planes being displayed in CADFEKO and the symmetry definition dialog. When applying symmetry in CADFEKO, the whole symmetric model should be created, including ports, sources, loads and so forth. The fact that it is not necessary to only create a section of the model makes it very easy to switch between a solution that employs symmetry and one that does not, or adjust the symmetry properties of the model without any geometry or mesh modifications. Symmetry planes must be set before meshing, though the type of symmetry may possibly be altered afterwards. During meshing CADFEKO will validate that the geometry to be meshed does indeed adhere to the specified model symmetry (both geometric symmetry as well as symmetry of excitation and loads where magnetic or electric symmetry is concerned). If the model is found not to adhere to the specified type of symmetry, CADFEKO will abort the meshing process and provide a list of objects in the model that break the symmetry. Finally, note the following: · Some ports (such as the wire port) influence the meshing in CADFEKO. Therefore, even if some ports are not loaded or excited, these still need to be defined symmetrically in the model for meshing to be successful. · Geometry and/or the mesh of a model may appear to be symmetrical while the CADFEKO symmetry tests indicate this not to be so. Possible reasons include tolerances in the model, or a redundant geometry point (vertex) on either side of the symmetry plane. In such a case it may be useful to delete half of the model, and then use the mirror operation to ensure a symmetrical model, rather than to try and resolve each asymmetry. This is particularly relevant when working with imported CAD geometry or imported meshes where there may be slight differences with respect to tolerances. Example 1: Utilization of symmetry for a rectangular horn antenna In Figure 4 a horn antenna is shown, excited with a dominant mode, rectangular waveguide port (a full description of the problem can be found in the FEKO Example Guide). The plane z=0 is clearly not a geometric symmetry plane, while the other two planes are. The plane y=0 is a plane of electric symmetry, since the incident wave is electrically polarized in the y-direction and this is already a geometric symmetry. The plane x=0 is a plane of magnetic symmetry, since the incident magnetic field is normal to this plane and the associated electric field is tangential to it, together with the fact that this is also a geometric symmetry plane. The symmetry properties of the antenna are as follows: Symmetry type x = 0 y = 0 z = 0 Geometric √ √ Electric √ Magnetic √ Figure 4: Electric and magnetic planes of symmetry of the horn antenna problem. The problem is now solved using the MoM, with various combinations of symmetry planes, with the computational costs noted. No near or far field requests were made, in order to isolate the impact of symmetry on computational cost as much as possible. The results are as follows: Symmetry applied Memory limit Memory [MByte] Runtime [relative] x = 0 plane y = 0 plane z = 0 plane - - - - 125.988 1.000 Geometric - - - 126.144 0.715 Geometric Geometric - - 126.159 0.562 Magnetic - - No 63.628 0.376 Magnetic - - Yes 32.424 1.833 Magnetic Geometric - No 63.643 0.231 Magnetic Geometric - Yes 32.439 1.825 - Electric - No 65.105 0.424 - Electric - Yes 34.120 1.900 Geometric Electric - No 65.120 0.269 Geometric Electric - Yes 34.135 1.900 Magnetic Electric - No 33.124 0.177 Magnetic Electric - Yes 9.899 0.914 Note the following: · Runtimes relative to the case of no symmetry is shown. These results are indicative of the relative effects of symmetry on overall runtime. · As can be seen, the computational cost reduction effect of either an electric or magnetic symmetry plane is practically the same. · Clearly, geometric symmetry has some advantages, but not as much as electric and magnetic symmetry. Geometric symmetry will speed up the setup of the triangle integrals, and especially when large meshes are used and will lead to a slight reduction in required memory due to the reduced geometry that needs to be stored. · Regarding the "Memory limit" column: FEKO can exploit electric/magnetic symmetry to minimize either runtime, or memory usage. FEKO's first priority is to minimize runtime, therefore FEKO will only partially exploit the benefits of symmetry with regards to memory usage, should sufficient memory be available (in this case a factor 2 reduction in memory is obtained per electric/magnetic symmetry plane). Should sufficient memory not be available for runtime minimization, memory usage is minimized instead (in this case a factor 4 reduction in memory is obtained per electric/magnetic symmetry plane). · There are some overheads such as the storing of the geometry which cause the memory reduction to not be exact (i.e. not exactly 1/2, 1/4 or 1/16 for the various cases). · For FEM/MoM, the benefits will depend upon the the number of FEM tetrahedra compared to MoM surface triangles. For the pure FEM, a memory reduction by at most a factor 2 can be obtained, whereas for the MoM it is a factor of 4. Example 2: Utilization of symmetry for a dipole array Consider two dipoles and a cornered PEC plate between the dipoles. If symmetry is to be applied, the first consideration is whether there is geometric symmetry. There are 3 planes of symmetry, at X=0, Y=0 and Z=0, so without any further considerations, we can at least set geometric symmetry on these 3 planes. The next question then is if these geometric symmetry planes can be set to electric or magnetic symmetry (to exploit the saving in computational resources). The sources will dictate the setting of symmetry. Consider the following sets of sources and their respective symmetry settings: 12. The first dipole is excited with 1 V and 0 degrees phase, and the second dipole with 1 V and 45 degrees phase. 13. Both dipoles are excited with 1 V and 0 degrees phase. For Case 1 there is no symmetry in the sources and all symmetry planes are set to geometric symmetry only. For Case 2 there is perfect symmetry in the sources. We consider therefore the fields of the two dipoles using the definitions from Figure 1 and Figure 2. For the Z=0 plane the doughnut shaped electric fields will be normal to the Z=0 plane and therefore non-zero. There will not be a tangential component of the electric field at the Z=0 plane (the dipoles are vertically polarised). Therefore for the Z=0 plane, we have electric symmetry. For the Y=0 plane there will be a tangential component of the electric field in this plane but not a tangential magnetic field component (the magnetic fields will be normal to the Y=0 plane). Therefore for the Y=0 plane, we have magnetic symmetry. For the X=0 plane, consider the combined electric fields of each dipole at this plane. The fields are vertically polarised and will each be tangential and in the same direction at the X=0 plane at any point in time. There is therefore a large tangential component of the electric fields at the X=0 plane. We therefore cannot set electric symmetry. The magnetic fields at any point in time will be tangential to this plane too, but in opposite directions (and same magnitudes), therefore they cancel and we have zero tangential magnetic fields at this plane. We can therefore set magnetic symmetry on the X=0 plane. Note that if the phases of the sources differed by 180 degrees, by similar reasoning we would have had electric symmetry on the X=0 plane. Recommendation In FEKO, the benefits of symmetry can be very significant. However, since symmetry cannot be exploited together with the MLFMM, the user should verify which of these features yield the largest reduction in computational cost and then only retain that feature in their model. The MLFMM is highly suited to structures of multiple wavelengths, but is not as beneficial in cases of small structures with very complex geometry. Should the latter structures be symmetric, they constitute a prime example of a problem class where symmetry can be very beneficial. When special Green functions are employed (planar and spherically layered media) the MLFMM is also not applicable. With special Green functions, symmetry should always be exploited when computational cost becomes an issue. This FAQ applies to: FEKO suite 5.4, FEKO suite 5.5, FEKO suite 6.0, FEKO suite 6.1, FEKO suite 6.2, FEKO suite 6.3
  44. 1 like
    Hi, Looks like your mesh size is coarse or try increasing tolerance so rbe3 will cover more nodes
  45. 1 like
    Dear Prakash, I am trying to do Pressfit simulation in Optistruct with NLSTAT having Dummy Load, SPC & NLPARM I am getting following error : *** ERROR # 1908 *** Case Control data LOAD=1 is not referenced by any bulk data relevant for used subcase type. LOAD = 1 which is dummy load collector is referenced in Load step, then also getting this error. Please address how to fix this issue. Thanks & Regards, Suraj
  46. 1 like
    Hi, you can use set CompList [hm_complist name] or set CompList [hm_entitylist comps name] the first will raise error if no comp found but the second won't
  47. 1 like
    Hi JM, Yes, in case you don't want to impose a velocity to control the hammer as i suggested above you can attach few springs to the nodes of the hammer and define the load vs displacement curve to the spring element using /PROP/SPRING card. Let us know how it goes! Thanks Vikas
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    Hello All, You can Follow below provided Video - Click here to watch entire Video
  50. 1 like
    Add the following codes (change to your needs) into "hmcustom.tcl" : set mypath "C:/Users/MYNAME/myscripts"; set top_menu [hm_framework getpulldowns] catch {$top_menu delete [.hmMainMenuBar index "MyMenu"]} catch {destroy $top_menu.custom} menu $top_menu.custom -tearoff 0 $top_menu insert 20 cascade -label "MyMenu" -menu $top_menu.custom set cat1 $top_menu.custom $cat1 add cascade -label "Category 1" -underline 0 -menu [menu $cat1.mnu1 -title "Cat-1"] $cat1.mnu1 add command -label "Script 1" -command "source {$mypath/script1.tcl}" -underline 0 $cat1.mnu1 add command -label "Script 2" -command "source {$mypath/script2.tcl}" -underline 0 $top_menu.custom add separator set cat2 $top_menu.custom $cat2 add cascade -label "Category 2" -underline 0 -menu [menu $cat2.mnu2 -title "Cat-2"] $cat2.mnu2 add command -label "Script 21" -command "source {$mypath/script21.tcl}" -underline 0 $cat2.mnu2 add command -label "Script 22" -command "source {$mypath/script22.tcl}" -underline 0 Start HM and you get your customized menus, see screenshot.