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How can I declare a variable in model.sdf file?

asked 2016-08-05 09:16:20 -0500

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Hi everyone,

I hope this is not a silly question. Is there a way to declare a variable in model.sdf file of a robot and use it multiple times? I've made a hexapod and it has some fixed values such as link length or width. If I want to change one leg's values I have to do the same for all the others. I believe this is done by xacro files in ROS but what if I want to do this without ROS?

Thanks in advance!

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answered 2016-08-05 12:15:38 -0500

chapulina
7504 ●2 ●23 ●54 https://louise.world/

You could use embedded ruby to generate parametrized models.

Here's an example of an SDF model with embedded ruby.
Here's an example of an SDF world with embedded ruby.

To regenerate the SDF from the erb template in the command line:

erb model.rsdf > model.sdf

Obs: see this answer.

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Thank you so much chapulina! This works very well. I was also thinking of something that I can implement a method in the sdf's API in order to declare a variable or anything I wish. For instance, when I look at the joint.sdf file in the sdformat directory, I can see the joint element's attributes or its elements. I tried to make my own element like declaration.sdf and gave a name and a value as attributes. However it didn't work at all. Would there be another way to do so?

elmuhn ( 2016-08-08 05:04:15 -0500 )edit

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Asked: 2016-08-05 09:16:20 -0500

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Last updated: Aug 05 '16

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How can I declare a variable in model.sdf file?