# bond lengths of A-A types and B-B types

Quote from OUYANG NIUCHNAG on July 19, 2020, 3:59 pmHi

I want to compute bond lengths of A-A bonds from lammps data file(lammps.straj-x y z). When I use the module of

in add modification to obtain the lengths of bonds, but there is no reaction. Could everyone give me some suggestion about how to get the lengths of A-A bond.compute bond lengths

Hi

I want to compute bond lengths of A-A bonds from lammps data file(lammps.straj-x y z). When I use the module of * compute bond lengths* in add modification to obtain the lengths of bonds, but there is no reaction. Could everyone give me some suggestion about how to get the lengths of A-A bond.

Quote from Alexander Stukowski on July 20, 2020, 11:56 amHi,

It seems you are still using and outdated version OVITO (v2.9.0 or 3.0.0-dev). The

Compute Bond Lengthsfunction was only part of OVITO in the past.Before I get to OVITO 3, let me tell you that the

Compute Bond Lengthsmodifier stores the computed lengths as new properties of the individual bonds. These values are not immediately visible in any way, and you need to apply some additional function to visualise the information. TheColor Codingmodifier, for example, which uses a color map to turn each bond's length value into a corresponding bond color. Another useful function is theHistogrammodifier, which allows you to compute the statistical distribution of bond length values in your system.In the current version of OVITO (3.1.x), you need to use the

Compute Propertymodifier instead of theCompute Bond Lengthsmodifier to let OVITO compute the lengths of bonds and store the output values as a new bond property named "Length", as shown in the attached screenshot.The upcoming new OVITO Pro version 3.2 will provide a specific function for this, the

Bond Analysismodifier. This function lets you compute the length distributions separately for different combinations of atom types, e.g. A-A or B-B, and also the bond angle distribution. Let me know if you are interested in trying out a preview build of that new OVITO Pro version.-Alex

Hi,

It seems you are still using and outdated version OVITO (v2.9.0 or 3.0.0-dev). The *Compute Bond Lengths* function was only part of OVITO in the past.

Before I get to OVITO 3, let me tell you that the *Compute Bond Lengths* modifier stores the computed lengths as new properties of the individual bonds. These values are not immediately visible in any way, and you need to apply some additional function to visualise the information. The *Color Coding* modifier, for example, which uses a color map to turn each bond's length value into a corresponding bond color. Another useful function is the *Histogram* modifier, which allows you to compute the statistical distribution of bond length values in your system.

In the current version of OVITO (3.1.x), you need to use the *Compute Property* modifier instead of the *Compute Bond Lengths* modifier to let OVITO compute the lengths of bonds and store the output values as a new bond property named "Length", as shown in the attached screenshot.

The upcoming new OVITO Pro version 3.2 will provide a specific function for this, the *Bond Analysis* modifier. This function lets you compute the length distributions separately for different combinations of atom types, e.g. A-A or B-B, and also the bond angle distribution. Let me know if you are interested in trying out a preview build of that new OVITO Pro version.

-Alex

**Uploaded files:**

- You need to login to have access to uploads.