# Change Properties in joints using ID

**URL:** <https://forum.itascainternational.com/t/change-properties-in-joints-using-id/2032>\
**Category:** UDEC\
**Tags:** tips, suggestions\
**Created:** [April 7, 2025, 9:47pm UTC](https://forum.itascainternational.com/t/change-properties-in-joints-using-id/2032 "2025-04-07T21:47:26Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![MichaelK](https://avatars.discourse-cdn.com/v4/letter/m/ccd318/32.png) [@MichaelK](https://forum.itascainternational.com/u/MichaelK)\
**Post date:** [April 7, 2025, 9:47pm UTC](https://forum.itascainternational.com/t/change-properties-in-joints-using-id/2032/1 "2025-04-07T21:47:26Z")

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Greetings to all,

I would like help with the following (if possible..):

Back in **UDEC 6** when you built the model with the “crack” command you could set an ID to each crack. This way you could easily use these cracks with the specific ID’s as joint sets.

Afterwards when setting properties for each joint you could use that specific ID and change easily the properties for each joint set.

For example you could build the geometry of a slope with the crack command like the following:

_crack x1 y1 x2 y2 id 1001_

_crack x3 y3 x4 y4 id 2001_

_…_

_crack xn yn xn+1 yn+1 id 9001_

After setting the properties for 3 different joint sets (e.g. jmat 11,21,31) you could easily change the properties from the default (jmat 1) using the following command:

_change jmat 11 range jmat 1 id 3001_

_change jmat 21 range jmat 1 id 2001_

_change jmat 31 range jmat 1 id 9001_

Now UDEC will select the cracks with the specific ID and set them the specific property.

I am trying to apply the same scheme in UDEC 7. When building the model with the same method the cracks seem to take the specific ID that I give them. However, when trying to change the properties with the respective command “block contact change..” it does not change any contacts or it changes 1-2 contacts with the specific ID, when I see in the GIIC window for example that this crack has 1800+ contacts with that ID.

I am writing the command as follows:

_Block contact change mat 10 range id 1001_

Am I missing something in the command or the “ID” for cracks is not working in UDEC 7 as it did in UDEC 6?

Thanks in advance for any suggestions / help.

BR,

Michael

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<div class="post-metadata">

**Author:** ![MichaelK](https://avatars.discourse-cdn.com/v4/letter/m/ccd318/32.png) [@MichaelK](https://forum.itascainternational.com/u/MichaelK)\
**Post date:** [April 8, 2025, 8:08am UTC](https://forum.itascainternational.com/t/change-properties-in-joints-using-id/2032/2 "2025-04-08T08:08:05Z")

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Greetings again,

It looks like I resolve it..  
The command sort of changed its syntax and the new one is:

_Block contact change mat 10 range jointset-id 1001_

Now it changes all the contacts with the respective ID.

BR,  
Michael