Material density setting issue.

[Thom Ivancso]

I have a lisp routine that is to allow the user the ability to change the material density of a selected part, by picking the material type off of a table. The command I am using to set the part density in my routine is such

(sd-call-cmds (set_part_base_density :parts parts :dens density))

Now if I select the material Aluminum from the list it has a density of .098 and change the part to this it completes without errors, however when I open the Parts And Assembly Menu | Settings | Base Density to check the changed part I get the following feedback the density shows as 3.540474616 instead of .098.

I have tried several different conversions to get the right information to display but nothing seems to be working.

I have even tried changing the instance of the part instead of the base but still I get the same answer as above.

Here is my table information

(sd-create-logical-table "Material-Density-List"
	:columns '(:Material :Density :Density_g)
	:columnNames '("Material Type"  "Density lb/in3" "Density g/cm3")
	:types '(:string :mass  :string)
	:units '( nil    :lb   nil)
	:contents  '(("Acrylic"    0.043 "1.190")
		     ("Alumina"    0.140 "3.875")
		     ("Aluminum"   0.098 "2.713")
		     ("BK-7 GLASS" 0.091 "2.510")
		     ("Brass"      0.308 "8.525")
		     ("Delrin"     0.055 "1.522")
		     ("Ertalyte"   0.050 "1.384")
		     ("Invar"      0.292 "8.083")
		     ("Molybdenum" 0.373 "10.324")
		     ("Semitrol"   0.048 "1.328")
		     ("Silicon"    0.084 "2.325")
		     ("Stainless"  0.287 "7.944")
                     ("Steel"      0.283 "7.833")
		     ("Teflon"     0.080 "2.214")
		     ("UHMW"       0.034 "0.941")
		    )
)

Has anyone tried to do something similar and ran into this problem?

Cheers
Thom

[Andy Poulsen]

Hi Thom,

I believe the problem is that OSDM expects all units to be in internal units, so when you set the density in question, you are setting it to .098 g/mm^3 instead of .098 lb/in^3. Then when you inquire the density, OSDM automatically converts it to user units (i.e. lb/in^3), which is 3.540...

I think your problem can be easily solved by simply adding a function call:

(sd-call-cmds (set_part_base_density :parts parts :dens (sd-user-to-sys-units :density density)))

the function (sd-user-to-sys-units ...) is very useful for converting whatever units the user is using into sys units (as is the corresponding function (sd-sys-to-user-units ...).

I hope this helps!

Good luck!

andy

[Thom Ivancso]

Hello Andy,

Thanks I spaced that one completely..


Cheers
Thom

[Michel Gendron]

Stupid question... In v13.01 where is the "command help" I cannot find it! I want to know all the parameter fo sd-sys-to-user-units and I can't find it!

Thanks

[Thom Ivancso]

Hello Michel,

Try this path for the help files in the Intergration kit.

C:\Program Files\CoCreate\OSD_Modeling_2005\help\osdm\Common\documentation\integration_kit\index.html


hth

Cheers
Thom