I am using ArcGIS Pro 2.0.1. I'm attempting to create a model to save me some time in the long run, just executing some repetitive raster functions. The model runs properly if I put in a static output name (i.e. one output raster that gets overwritten by the subsequent runs).
The problem, as far as I can tell, is that the rasters I am importing are exported from Oasis Montaj as .gxf files, which are able to be read by ArcGIS but are not listed as a raster format in the raster iterator. Because of this, the name from the raster is being read as "**.gxf", so if I try to set the output as %Name%_ex, the model tries to output the name as "**.gxf_ex" and throws an error. What I'm trying to do is have the final name / raster as "**_ex.gxf" and I'm not entirely certain how to do that (not sure how to add strings together properly in model builder). I also tried naming the output %i% as a test, but it only named the output "0" and wrote over it continuously.