Measure the dimensions of a shape

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Hello

I'm new to Houdini, and I would like to know the dimensions (x,y,z) of a given geometry.
Thank you

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Hi,

You can create a Detail Wrangle and write something like this:

v@size = getbbox_size ( 0 );

It will store the size of the geo as size detail attribute for the entire geo.
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Thank you very much.

I don't see a Detail Wrangle node, or u mean to simply use attribwrangle? After I added "v@size = getbbox_size ( 0 );"
to the attribwrangle node, where exactly I can see the detail attribute for the entire geo?

Thank you
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Matan_Shilo
Thank you very much.

I don't see a Detail Wrangle node, or u mean to simply use attribwrangle? After I added "v@size = getbbox_size ( 0 );"
to the attribwrangle node, where exactly I can see the detail attribute for the entire geo?

Thank you

Just set the attribute wrangle node parameter "run over" to detail and it will create a detail attribute for you. They didn't make a detail wrangle, but it is easy enough to chose the class yourself.
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If you just want to know while you're working on it you can middle click the node. Sometimes useful to get an idea of what noise scales to use, etc.
Edited by Soothsayer - 2021年7月19日 03:24:50
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Hey guys! I'm trying to do a similar thing. I'd just like to see how big a mesh is haha. I understand that if I middle mouse click a node, it tells me the size. However, I'm not sure what that size IS. For example, when you create a box, the box defaults to "1,1,1" But is that in centimeters? I learned that I can change the scale of the grid, which is cool, but I'd rather not "eye" things out. Is there a way to determine the absolute scale of an object? It's important for me, expecially if I'm doing things that arent always going to be boxes.
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If not changed, 1 unit is 1m.
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Konstantin Magnus
If not changed, 1 unit is 1m.

Sort of. Houdini is largely unitless, but there are contexts where the units do matter. The units are largely determined by fiat.
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Konstantin Magnus
If not changed, 1 unit is 1m.
ah ok! how would I change that? would that be in
edit > Preferences > Hip File options ?
I thought that only changed the scale of the grid?
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jsmack
Konstantin Magnus
If not changed, 1 unit is 1m.

Sort of. Houdini is largely unitless, but there are contexts where the units do matter. The units are largely determined by fiat.
Oh interesting. What is Fiat?
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Pmiller001
jsmack
Konstantin Magnus
If not changed, 1 unit is 1m.

Sort of. Houdini is largely unitless, but there are contexts where the units do matter. The units are largely determined by fiat.
Oh interesting. What is Fiat?

Meaning by declaration. I.e. the object is 1 meter high because I've defined 1 unit = 1 meter. This can cause problems when importing a model created by someone else that has 1 unit representing a different scale, such as cm or inches. The model will look too large in my scene in that case. The publisher of the model will have to communicate what scale was used to create the model.
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Pmiller001
ah ok! how would I change that? would that be in
edit > Preferences > Hip File options ?
I thought that only changed the scale of the grid?

Changing the preference does mostly nothing. It may change some defaults for dynamics constants, but mainly it affects how the film back and focal length units are converted into scene units for depth of field purposes. It might affect how FBX is imported now that scale can be applied on import. (fbx units were ignored in prior versions)
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If you use Gaz and fluid it's strongly advised to keep the 1 unit 1 meter or when doing FX you do matrix transform to come there there...
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