# 3DEC **URL:** https://forum.itascainternational.com/c/3dec/6.md [Latest](https://forum.itascainternational.com/latest.md) · [Categories](https://forum.itascainternational.com/categories.md) · [Tags](https://forum.itascainternational.com/tags.md) --- ## [About the 3DEC category](https://forum.itascainternational.com/t/about-the-3dec-category/13)
**Author:** [@jhazzard](https://forum.itascainternational.com/u/jhazzard)\ **Replies:** 1\ **Last updated:** [February 18, 2023, 2:58am UTC](https://forum.itascainternational.com/t/about-the-3dec-category/13 "2023-02-18T02:58:23Z")
3DEC is a three-dimensional numerical modeling code for advanced geotechnical analysis of soil, rock, ground water, structural support, and masonry. 3DEC simulates the response of discontinuous media (such as jointed roc… --- ## [Hydro-mechanical Calculation](https://forum.itascainternational.com/t/hydro-mechanical-calculation/1053)
**Author:** [@DariushJ](https://forum.itascainternational.com/u/DariushJ)\ **Replies:** 13\ **Last updated:** [September 1, 2026, 3:35pm UTC](https://forum.itascainternational.com/t/hydro-mechanical-calculation/1053 "2026-09-01T15:35:43Z")
Hi, I try to understand how 3DEC performs hydro-mechanical calculations. From manual of 3DEC 5.20 I understood a little, but I will be grateful if someone can simply explain the computation loop from start point to the … --- ## [How to group heading and benching portion separate in a tunnel model?](https://forum.itascainternational.com/t/how-to-group-heading-and-benching-portion-separate-in-a-tunnel-model/2391)
**Author:** [@tanvikedare](https://forum.itascainternational.com/u/tanvikedare)\ **Replies:** 1\ **Last updated:** [June 19, 2026, 1:22pm UTC](https://forum.itascainternational.com/t/how-to-group-heading-and-benching-portion-separate-in-a-tunnel-model/2391 "2026-06-19T13:22:17Z")
Hi all. Ive been trying to use the tunnel function in my 3dec v 5.2 to create a tunnel but in order to group it in two parts I am unable to model the false invert and bifurcate the tunnel in two, basically heading and be… --- ## [Apply stress in 3DEC](https://forum.itascainternational.com/t/apply-stress-in-3dec/607)
**Author:** [@rdhoaziz](https://forum.itascainternational.com/u/rdhoaziz)\ **Replies:** 6\ **Last updated:** [May 11, 2026, 4:28pm UTC](https://forum.itascainternational.com/t/apply-stress-in-3dec/607 "2026-05-11T16:28:03Z")
Hello, I would like to ask question about how to apply a stress to a column. I have a column or block bar with 0.5m x 0.5m x 5m (x,y,z) as an elastic body. I would like to apply a triangular stress 3MPa at the top of the… --- ## [Heterogeneity in the properties of material of particles](https://forum.itascainternational.com/t/heterogeneity-in-the-properties-of-material-of-particles/2378)
**Author:** [@ShivamPandey](https://forum.itascainternational.com/u/ShivamPandey)\ **Replies:** 2\ **Last updated:** [April 21, 2026, 12:49pm UTC](https://forum.itascainternational.com/t/heterogeneity-in-the-properties-of-material-of-particles/2378 "2026-04-21T12:49:47Z")
I am working on slope modelling using the Voronoi block approach in 3DEC to represent a heterogeneous rock mass/overburden dump. I would like to assign different material properties to individual Voronoi blocks in order … --- ## [3dec prestressed anchors](https://forum.itascainternational.com/t/3dec-prestressed-anchors/2370)
**Author:** [@mariyanD](https://forum.itascainternational.com/u/mariyanD)\ **Replies:** 1\ **Last updated:** [April 9, 2026, 7:59pm UTC](https://forum.itascainternational.com/t/3dec-prestressed-anchors/2370 "2026-04-09T19:59:40Z")
HI! When i try to prestress cable bolts in 3dec, i get the following error: FEMLine::SetLsys(): fail to define local coord. sys. While processing line 282 of source GUI Console I have run a model without tension appl… --- ## [Examples for Coupling of UDEC/3DEC and FLAC/FLAC3D](https://forum.itascainternational.com/t/examples-for-coupling-of-udec-3dec-and-flac-flac3d/836)
**Author:** [@xiongyu](https://forum.itascainternational.com/u/xiongyu)\ **Replies:** 16\ **Last updated:** [March 2, 2026, 3:59pm UTC](https://forum.itascainternational.com/t/examples-for-coupling-of-udec-3dec-and-flac-flac3d/836 "2026-03-02T15:59:57Z")
Is there any examples (codes) for coupling of UDEC/3DEC and FLAC/FLAC3D? --- ## [Zone groups not recognized properly after block merge](https://forum.itascainternational.com/t/zone-groups-not-recognized-properly-after-block-merge/2322)
**Author:** [@emegag](https://forum.itascainternational.com/u/emegag)\ **Replies:** 3\ **Last updated:** [January 26, 2026, 2:47pm UTC](https://forum.itascainternational.com/t/zone-groups-not-recognized-properly-after-block-merge/2322 "2026-01-26T14:47:00Z")
Hi all, I’m running into confusing behaviour with zone groups after block merge in 3DEC 9.0, and I’m trying to understand whether this is expected behaviour or a bug. I want to create two stacked blocks, merge them int… --- ## [Get the damped and total released energy in 3dec for Rigid blocks](https://forum.itascainternational.com/t/get-the-damped-and-total-released-energy-in-3dec-for-rigid-blocks/2309)
**Author:** [@yopiprabowo](https://forum.itascainternational.com/u/yopiprabowo)\ **Replies:** 1\ **Last updated:** [December 23, 2025, 4:56pm UTC](https://forum.itascainternational.com/t/get-the-damped-and-total-released-energy-in-3dec-for-rigid-blocks/2309 "2025-12-23T16:56:16Z")
Hi! I have seen that 3dec can track the released and damped energy at each timestep, but it seems the feature is only available for deformable blocks. How can I do that for the rigid blocks formulation? --- ## [Contacts disappear during meshing phase](https://forum.itascainternational.com/t/contacts-disappear-during-meshing-phase/2295)
**Author:** [@Theophile](https://forum.itascainternational.com/u/Theophile)\ **Replies:** 2\ **Last updated:** [December 1, 2025, 2:40pm UTC](https://forum.itascainternational.com/t/contacts-disappear-during-meshing-phase/2295 "2025-12-01T14:40:32Z")
Hi again, everyone! On another model, we have been facing difficulties getting a functional mesh: during meshing, some contacts “disappear”. We had to do some trial-and-error to get a mesh with the full contact set and… --- ## [(Apparent?) tensile rupture in joint with a hydrostatic model](https://forum.itascainternational.com/t/apparent-tensile-rupture-in-joint-with-a-hydrostatic-model/2285)
**Author:** [@Theophile](https://forum.itascainternational.com/u/Theophile)\ **Replies:** 6\ **Last updated:** [November 26, 2025, 7:54am UTC](https://forum.itascainternational.com/t/apparent-tensile-rupture-in-joint-with-a-hydrostatic-model/2285 "2025-11-26T07:54:24Z")
Hi everyone! Doing some tests on hydromechanics in 3DEC, I came up ith this situation I cannot explain: when considering pore pressure in joints (fluid not configured), I get tensile rupture even when specifying extreme… --- ## [On the representation of normal displacements of curved contacts](https://forum.itascainternational.com/t/on-the-representation-of-normal-displacements-of-curved-contacts/2286)
**Author:** [@Theophile](https://forum.itascainternational.com/u/Theophile)\ **Replies:** 2\ **Last updated:** [November 24, 2025, 4:11pm UTC](https://forum.itascainternational.com/t/on-the-representation-of-normal-displacements-of-curved-contacts/2286 "2025-11-24T16:11:30Z")
Hi everyone ! That will be two posts in a row for me today :slight\_smile:. We study the impacts on considering irregular contacts in 3DEC. Thanks to the block merge commands, we can import meshes that were created usi… --- ## [Error- end face is missing from tunnel](https://forum.itascainternational.com/t/error-end-face-is-missing-from-tunnel/2266)
**Author:** [@tanvikedare](https://forum.itascainternational.com/u/tanvikedare)\ **Replies:** 1\ **Last updated:** [November 8, 2025, 10:41pm UTC](https://forum.itascainternational.com/t/error-end-face-is-missing-from-tunnel/2266 "2025-11-08T22:41:45Z")
in 3dec i tried creating a circular tunnel using the existing code in tutorial file for tunnel. but im getting this error. the code is as foll. tx1=txc+tr\*cos(360\*degrad) tx2=txc+tr\*cos(337.5\*degrad) tx3=tx… --- ## [How to reduce the computation time for coupled HM flow in disk-shape fractures](https://forum.itascainternational.com/t/how-to-reduce-the-computation-time-for-coupled-hm-flow-in-disk-shape-fractures/2257)
**Author:** [@LorenZafrilla](https://forum.itascainternational.com/u/LorenZafrilla)\ **Replies:** 1\ **Last updated:** [October 23, 2025, 2:12pm UTC](https://forum.itascainternational.com/t/how-to-reduce-the-computation-time-for-coupled-hm-flow-in-disk-shape-fractures/2257 "2025-10-23T14:12:21Z")
Hi, I’m working with printed 3D samples with disk-shape fractures inside and try to replicate my permeability tests with different gradients and confining stress with 3DEC. To restrict the flow only inside the disks, I… --- ## [Load rate controlled UCT](https://forum.itascainternational.com/t/load-rate-controlled-uct/2250)
**Author:** [@EdgarO31](https://forum.itascainternational.com/u/EdgarO31)\ **Replies:** 5\ **Last updated:** [October 16, 2025, 3:40pm UTC](https://forum.itascainternational.com/t/load-rate-controlled-uct/2250 "2025-10-16T15:40:43Z")
Hello, I am trying to model an unconfined compression test on a mortar cube to replicate to what I got from my lab test, which followed the ASTM procedure (a load rate controlled test, instead of strain controlled). I h… --- ## [Hybrid bolt-Dowel element storage structures](https://forum.itascainternational.com/t/hybrid-bolt-dowel-element-storage-structures/2247)
**Author:** [@SohG](https://forum.itascainternational.com/u/SohG)\ **Replies:** 2\ **Last updated:** [October 7, 2025, 3:33pm UTC](https://forum.itascainternational.com/t/hybrid-bolt-dowel-element-storage-structures/2247 "2025-10-07T15:33:37Z")
Hi, I am modeling a rock slope in 3dec using the topography of the site. When I define Hybrid bolts from geometry (lines), I get the following error, (dowel element storage structures) and while running I get an error th… --- ## [Flow rate model calculation](https://forum.itascainternational.com/t/flow-rate-model-calculation/2188)
**Author:** [@lucasbmachado](https://forum.itascainternational.com/u/lucasbmachado)\ **Replies:** 6\ **Last updated:** [September 24, 2025, 8:21pm UTC](https://forum.itascainternational.com/t/flow-rate-model-calculation/2188 "2025-09-24T20:21:08Z")
Hello! I want to calculate the flow rate in a DFN model. I used the function flowplane.zone.discharge to obtain the flow vectors within a loop foreach over flowplane.zone.list, with block fluid crack-flow on enabled. Th… --- ## [Distance between a point/vector and a fracture](https://forum.itascainternational.com/t/distance-between-a-point-vector-and-a-fracture/2236)
**Author:** [@lucasbmachado](https://forum.itascainternational.com/u/lucasbmachado)\ **Replies:** 1\ **Last updated:** [September 19, 2025, 5:35pm UTC](https://forum.itascainternational.com/t/distance-between-a-point-vector-and-a-fracture/2236 "2025-09-19T17:35:26Z")
Hello everyone, I want to find all nodes/points or vectors (positions) inside my fracture (distance = 0). When I use fracture.position, I only get the center vector, but I don’t want to compare the center of the fractur… --- ## [Error (newccell): block vertex outside cell space](https://forum.itascainternational.com/t/error-newccell-block-vertex-outside-cell-space/2235)
**Author:** [@Mahdi.S](https://forum.itascainternational.com/u/Mahdi.S)\ **Replies:** 1\ **Last updated:** [September 18, 2025, 2:02pm UTC](https://forum.itascainternational.com/t/error-newccell-block-vertex-outside-cell-space/2235 "2025-09-18T14:02:22Z")
Hello everyone, I am simulating a large-scale open pit in 3DEC (FEM with a single major structure only) and I am encountering the following error: \*\*\* error (newccell): block vertex outside cell space. Could anyone … --- ## [Joint Surface Area](https://forum.itascainternational.com/t/joint-surface-area/2190)
**Author:** [@FauzanYudho](https://forum.itascainternational.com/u/FauzanYudho)\ **Replies:** 5\ **Last updated:** [August 31, 2025, 2:53pm UTC](https://forum.itascainternational.com/t/joint-surface-area/2190 "2025-08-31T14:53:26Z")
Hello all, new user here. I would like to kindly ask for advice on how to obtain the total surface area of all the joints in my 3DEC model. Thank you in advance. --- ## [Determination of strain softening parameters (SSoft Model)](https://forum.itascainternational.com/t/determination-of-strain-softening-parameters-ssoft-model/2212)
**Author:** [@EdgarO31](https://forum.itascainternational.com/u/EdgarO31)\ **Replies:** 2\ **Last updated:** [August 20, 2025, 11:04pm UTC](https://forum.itascainternational.com/t/determination-of-strain-softening-parameters-ssoft-model/2212 "2025-08-20T23:04:13Z")
Hello, everyone! I’m new to 3DEC and also new to numerical modeling in general. I’m thinking on using strain softening Mohr-Coulomb to model concrete, but I’m struggling trying to understand how to determine the curves … --- ## [Applying Body Force to 3DEC zones](https://forum.itascainternational.com/t/applying-body-force-to-3dec-zones/2196)
**Author:** [@RRay](https://forum.itascainternational.com/u/RRay)\ **Replies:** 1\ **Last updated:** [August 14, 2025, 6:14pm UTC](https://forum.itascainternational.com/t/applying-body-force-to-3dec-zones/2196 "2025-08-14T18:14:03Z")
How to apply body force on all the zones in a block? The 3DEC manual says that “block gridpoint apply force-y” will only apply to the block gridpoints and not the zone gridpoints. In FLAC3D I had been using this code “… --- ## [Fish operator, hist command, local and global variables](https://forum.itascainternational.com/t/fish-operator-hist-command-local-and-global-variables/2202)
**Author:** [@Damir](https://forum.itascainternational.com/u/Damir)\ **Replies:** 2\ **Last updated:** [August 13, 2025, 9:54pm UTC](https://forum.itascainternational.com/t/fish-operator-hist-command-local-and-global-variables/2202 "2025-08-13T21:54:03Z")
Hi everybody! This question may be trivial, so sorry in advance. I have, let’s say, 200 cross sections throughout the complicated structure. Sections are used to integrate and plot various outputs. I use fish operator a… --- ## [Clarification on dip calculation from principal stress direction cosines in 3DEC](https://forum.itascainternational.com/t/clarification-on-dip-calculation-from-principal-stress-direction-cosines-in-3dec/2199)
**Author:** [@emegag](https://forum.itascainternational.com/u/emegag)\ **Replies:** 3\ **Last updated:** [August 13, 2025, 1:24am UTC](https://forum.itascainternational.com/t/clarification-on-dip-calculation-from-principal-stress-direction-cosines-in-3dec/2199 "2025-08-13T01:24:13Z")
Hi all, I’m working with principal stress direction cosines exported from 3DEC, and I’m trying to understand how the software converts these direction cosines into dip and dip direction values shown in the built-in ster… --- ## [Unexpected Gaps in Axial Tension Simulation of Shell Specimen in 3DEC](https://forum.itascainternational.com/t/unexpected-gaps-in-axial-tension-simulation-of-shell-specimen-in-3dec/2194)
**Author:** [@sanhtra](https://forum.itascainternational.com/u/sanhtra)\ **Replies:** 0\ **Last updated:** [August 5, 2025, 7:55am UTC](https://forum.itascainternational.com/t/unexpected-gaps-in-axial-tension-simulation-of-shell-specimen-in-3dec/2194 "2025-08-05T07:55:52Z")
Dear Itasca team, I am simulating an axial tension test on a shell specimen. In the model, the two end segments of the shell are connected to deformable blocks via rigid connections (constrained in all translational deg… --- ## [How to obtain the gridpoint acceleration in 3DEC](https://forum.itascainternational.com/t/how-to-obtain-the-gridpoint-acceleration-in-3dec/2180)
**Author:** [@JLUJYP](https://forum.itascainternational.com/u/JLUJYP)\ **Replies:** 3\ **Last updated:** [July 28, 2025, 2:57am UTC](https://forum.itascainternational.com/t/how-to-obtain-the-gridpoint-acceleration-in-3dec/2180 "2025-07-28T02:57:39Z")
Hi, How can I obtain the gridpoint acceleration in 3DEC, similar to what is shown in the FLAC below? Thanks in advance! --- ## [Clear all variables after each looping](https://forum.itascainternational.com/t/clear-all-variables-after-each-looping/2174)
**Author:** [@lucasbmachado](https://forum.itascainternational.com/u/lucasbmachado)\ **Replies:** 1\ **Last updated:** [July 19, 2025, 5:20pm UTC](https://forum.itascainternational.com/t/clear-all-variables-after-each-looping/2174 "2025-07-19T17:20:01Z")
Hi, I’m running a looped FISH script and would like to reset all variables, at the start of each iteration. Is there a command for clearing or reinitializing global and local variables during looping? --- ## [Joint HM coupling: pore pressure diffusion stuck](https://forum.itascainternational.com/t/joint-hm-coupling-pore-pressure-diffusion-stuck/2143)
**Author:** [@Theophile](https://forum.itascainternational.com/u/Theophile)\ **Replies:** 4\ **Last updated:** [July 15, 2025, 1:43pm UTC](https://forum.itascainternational.com/t/joint-hm-coupling-pore-pressure-diffusion-stuck/2143 "2025-07-15T13:43:36Z")
Hi there everyone! So, we are running some tests for possible fault reactivation under given imposed pore pressure. We started from the documentation example coupled-fast. When changing the model dimensions (from metri… --- ## [Principal stress direction vectors](https://forum.itascainternational.com/t/principal-stress-direction-vectors/2131)
**Author:** [@LeoBBL](https://forum.itascainternational.com/u/LeoBBL)\ **Replies:** 11\ **Last updated:** [July 3, 2025, 9:35pm UTC](https://forum.itascainternational.com/t/principal-stress-direction-vectors/2131 "2025-07-03T21:35:21Z")
Hi Everyone When obtaining the principal stress directions (with block.zone.stress.prin.dir ), do the vectors correspond to the actual orientation of the stresses or to the normal vectors of each principal plane? Thanks… --- ## [Simulating tunnel in landslide](https://forum.itascainternational.com/t/simulating-tunnel-in-landslide/2019)
**Author:** [@PietroF](https://forum.itascainternational.com/u/PietroF)\ **Replies:** 4\ **Last updated:** [June 5, 2025, 3:41pm UTC](https://forum.itascainternational.com/t/simulating-tunnel-in-landslide/2019 "2025-06-05T15:41:01Z")
Hi everyone! I have modeled a landslide in FLAC3D. I am trying to reproduce the stress state in a small portion (a box) of the landslide body, inside which a tunnel is located, in order to deepen the analysis on the con… [Next page](https://forum.itascainternational.com/c/3dec/6.md?page=1)