# vtkPlanes not making planes
**URL:** https://discourse.vtk.org/t/vtkplanes-not-making-planes/4611
**Category:** Development
**Created:** [November 9, 2020, 6:30pm UTC](https://discourse.vtk.org/t/vtkplanes-not-making-planes/4611 "2020-11-09T18:30:29Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Gilthalas](https://discourse.vtk.org/u/Gilthalas)
#### Post date: [November 9, 2020, 6:30pm UTC](https://discourse.vtk.org/t/vtkplanes-not-making-planes/4611/1 "2020-11-09T18:30:29Z")
I’m attempting to make a vtkPlanes object with the following Java code:
```
vtkPlanes planes = new vtkPlanes();
planes.SetPoints(planePoints);
planes.SetNormals(planeNormals);
```
Where `planePoints` is a `vtkPoints` object and `planeNormals` is a `vtkDataArray`. When I call `planes.GetNumberOfPlanes()`, it always returns 0. What am I missing? Is there something I need to do to make it forms the planes? As usual the documentation is less than informative. Thanks for any information you can provide.
---
### Author:  [@Keyn](https://discourse.vtk.org/u/Keyn)
#### Post date: [November 9, 2020, 7:35pm UTC](https://discourse.vtk.org/t/vtkplanes-not-making-planes/4611/2 "2020-11-09T19:35:44Z")
Not quite sure about the Java implementation of vtk, but typically in C++ I need to call a update function to make sure the output is as configured.
Does
```
planes.update();
```
exist, or work?
---
### Author:  [@Gilthalas](https://discourse.vtk.org/u/Gilthalas)
#### Post date: [November 9, 2020, 7:44pm UTC](https://discourse.vtk.org/t/vtkplanes-not-making-planes/4611/3 "2020-11-09T19:44:55Z")
I think I figured it out - for some reason `vtkDataArray` is initializable when it really shouldn’t be - you have to use something like `vtkDoubleArray` or `vtkFloatArray`