Flexsim vs. Witness

Hi there,

from 2001 until 2006, I worked as a senior consultant with Witness and I belong to the Flexsim Germany group since 2007. So you will find an of course subjective and incomplete comparison of me here:

Flexsim + :

- Modelling directly in 3D and impressing 3D capabilities. Very good for
presentations and therefore good for selling. Also the fly path capability
is very impressive and useful in this context. And it makes fun to work
with these things!

- Very impressing display models available for download.

- Large object library incl. crane, rack, robot etc. That can't be taken for
granted and isn't included e.g. in Witness.

- The GUI feature also makes a good impression and is useful.

- Same for Flexsim Chart.

- Prospects often asked, how a model can be documented - therefore it's
very good, that the model documentor is part of Flexsim. In Witness, it's
an extra tool and has to be paid.

- Also good to have 'ExpertFit' for free. Witness has something similar
called 'Own defined distribution', but 'ExpertFit' is easier to use in my
opinion.

- Multiple model triggers. There are less in Witness.

- I don't share the bad rating for the Flexsim documentation, because
every user gets a printed documentation! And I know from my
experience, that a lot of users want this, though they could prompt it on
the screen, too. In Witness, one only gets the online help, and this
can't be printed as a whole.

Flexsim - :

- Yes, there are only a few case studies available. Witness offers a lot of
them! In presentations, it's good to be able to mention case studies of the
prospect's sector, and it helps to be able to show one. I will try to
write one for every project, as far as the customer allows it.

- No automatic avoiding of multiple use of pseudo random number strings.
Witness does it, if the user wishes it.

- There are no example models on the install cd. I know, that models can
be downloaded from the forum, but they are not as easy to find and not
as structured as they could be on the install cd. On the other hand:
Which models to put on? The wishes will be individual.
Maybe the structure in the download area can be enhanced by creating
additional categories like e.g. Models/User Concept/ 'Robot', 'ASRS', 'Conveyor' etc.

- In my opinion, there should be more predefined commands/capabilities.
2 examples:

- If one has x flowitems of itemtype 1 and y flowitems of itemtype 2 in
a queue, then there should exist a command to get the number of e.g.
the flowitems 1 in the queue. At the moment, one for example has to write
a loop, what can be slow.
I know the thread www.flexsim.com/community/forum/threads/thread751, but it
might be a nice functionality to have this data already collected by a queue and a
rack. So that might also be a point for the development list.

- If a setup in the processor object needs an operator, one can tick a
box. Why not, if it needs an operator for repair?

- The Recorder object and the .avi maker aren't of good use, they should
be enhanced.

- The Flexscript code is longer than e.g. a Basic based code, caused e.g.
by the { , } and ; needed, and some commands are long, e.g.
setlabelnum(item,"labelxy",2.3); compared with
labelxy = 2.3 in Basic based code.
On the other hand, breaking the syntax rules of FlexScript (command(par1,par2) just
to have shorter code might lead to confusion and issues.

- The MTEI is hard to define in my opinion. Witness uses a wizard, which
works better.

- No allowance time for time tables possible. Example: If an operator
starts a 5 min. job, but the remaining time of its time table is only 3 min.,
then it should be able to define a max. allowance time for an object (here the
operator) to work longer. In case the work can be finished in the max.
allowance time, it will be finished. This is possible in Witness.
I know, that in a timetable, it's possible to use a pick option (down function task
sequence 1 und 2), that the operator finishes his job - but that's something else
than having an allowance time.

- It isn't possible to create a Flexsim state file (.fst), with which one can
reproduce a simulation run exactly, even if one avoids e.g. global
variables.
But it should be possible to reproduce a simulation run exactly, e.g.
if you want to show someone an error, that occurs only after let's say 1
real hour. With Witness, one can create such reproducable state files.


Witness + :

- See also the mentioned before in Flexsim -

- A lot of demo and example models on the install cd.

- Shift patterns can be imported quite easily using a .txt file.

- The .avi maker is useful.

- They provide power and free modelling objects.

- Witness has several model layers. One can easily link objects to specific layers. When one then makes e.g. layer x
invisible, then all objects linked to layer x are invisible. This for me seems to be more comfortable than to
put objects in Visual Tools and then to make them invisible in Flexsim.


Witness - :

- See also the mentioned before in Flexsim +

- No GUI feature.

- No direct 3D modelling. One has to transform the 2D model into a 3D one, what
costs a lot of time.

- 3D modelling is an extra license, what makes Witness 3D (called 'VR') more
expensive than Flexsim.

- The run speed adjustment doesn't work as well as in Flexsim.

- Not as flexible as Flexsim.