viklc
then I can read out the size of the components, but for a vector 4 and matrix 2, the size is 4. Therefore it is not possible to separate these from each other

BabaJ
Unless of course have you had any function 'complain' when one is provided yet it asks for the other by 'name', rather than looking at the data it provides?

BabaJ
They are the same data wise.

viklc
Hey BabaJ,

BabaJ
Unless of course have you had any function 'complain' when one is provided yet it asks for the other by 'name', rather than looking at the data it provides?

Yes exactly, that's the point 😊

I'm working on a tool, or rather a sub-tool, that makes it easier to work with attributes and to interact with them more flexible. For example, if the user provides a vector, the program can dynamically interact with it and provide user interface elements such as position or color components, similar to a vector 4 euler parms for normals rotation. For a matrix xform parameters or the matrix itself.

BabaJ
They are the same data wise.

At least that's what it looks like in Spreedsheat - and yes they are float at the end. But you can't access a matrix with square brackets, you use postfixes like .xx, yz and so on. And the getComp function is not too flexible either. And if it's purely a matter of fictionality, you quickly run into errors. For example, I can't assign an identity matrix to a vector 4, you wouldn't want to, but the programme can't tell the difference from the current point.
The same applies to the matrix operation - the results would be different.

I've tried this in Python as well, but run into the same problem - especially if you also want to separate array types, they are not returned as nested lists/tuples, but as a single tuple.

What works is filtering with the function attribtypeinfo. However, this additional information must be given, which only happens automatically if attributes are set with the AtttribCreate SOP, otherwise it must be set manually - which again makes the function useless in this case.

viklc
I'm working on a tool, or rather a sub-tool, that makes it easier to work with attributes and to interact with them more flexible. For example, if the user provides a vector, the program can dynamically interact with it and provide user interface elements such as position or color components, similar to a vector 4 euler parms for normals rotation. For a matrix xform parameters or the matrix itself.

animatrix_
Without Attribute Type Info metadata, you can't know. Because a vector can be a vector, or a normal, or a position, or a color, or an array of numbers, etc. I think the best way is to provide a menu dropdown based on the number of elements in the attribute.

vector4 tmp[];

// - att set to a vector4
p@att = {1,2,3,4};
tmp = set(@att); // {{1,1,1,1}, {2,2,2,2}, {3,3,3,3}, {4,4,4,4}} 

// - att set to a matrix2
2@att = {1,2,3,4};
tmp = set(@att); //{1,2,0,0}, {3,4,0,0}, {0,0,1,0}, {0,0,0,1}}

string data_type = (tmp[0].w == 0) ? "matrix2" : "vector4";

viklc
Yes, but at least you can filter the data types per se.

BabaJ
Why not 'pre filter' - when the user provides data, have them specify with a drop down menu - what type it is going to be.
Then you can create a detail attribute that keeps/stores that information - So all you have to do anywhere downstream is look at the specified type chosen and deal with that accordingly.

BabaJ
So you can maybe just put in an RFE for identifying attributes more specifically than what attribtype can give you.

viklc
Okey, after a few attempts it doesn't really seems possible to keep these two types apart.
For example, if you try to retrieve a Matrix2 attribute with getattrib() and don't explicitly refer to the data type, Houdini sees it as Vector4 - what BabaJ mentioned above. It can also be proved by adding a matrix2 to a dictionary, it will indeed say "vector4" as the type. So the "solution" above does not work in the end.

BabaJ
What solution are you referring too?

viklc
The simplest form of the query would be:
string data_type = (tmp.w == 0) ? "matrix2" : "vector4";

2@att;
printf(attribtype(getattrib(0, ... "att"...))); // vector 4

matrix2 att = getattrib(0, ... "att"...);

BabaJ
If you do the pre setup like mentioned before - Have user define the type and save that info as an attribute:

viklc
they could also come from a cache / imported geometry........ the user should simply select or enter the attribute, but without the indication of what type it is,

BabaJ
If the user has to type or enter anyway - might as well 'force' the user to define what it is they are entering, e.g. drop down menu selection or string entered with full type attribute spelt out for parsing.

BabaJ
Otherwise if you really want a more streamlined operation -- either wait that many others want the same (filed a RFE) feature for a function or addendum to existing function -- OR -- perhaps dig into the HDK and do it with C++, if that's possible there, idk.