Get CPT Category

<?php


remove_action( 'genesis_loop', 'genesis_do_loop' ); // Remove default Genesis Loop
add_action( 'genesis_loop', 'child_cpt_post_loop' ); // Add custom post type loop
/**
 * Build the custom loop to display project category
 *
 * @author Greg Rickaby
 * @since 1.0.0
 */
function child_cpt_post_loop() {

    if ( is_category() ) {
        $cat = get_query_var( 'cat' );
        $cptcat = get_category($cat);
        $cptcat->slug;
    }

    $loop = new WP_Query( array(
        'post_type' => 'project',
        'posts_per_page' => 20,
        'category_name' => $cptcat->slug,
    ) );

    while ( $loop->have_posts() ) : $loop->the_post(); ?>
                <div class="post-<?php the_ID(); ?> post project project-category">
                    <div class="entry-content">
                    <?php // Check for download link
                        if ( genesis_get_custom_field( '_cmb_project_download' ) ) { ?>
                    <div class="project-download">
                        <a href="<?php echo genesis_get_custom_field( '_cmb_project_download' ); ?>" title="<?php the_title();?>" class="sfdl">
                            <span>
                                <b>Download</b>
                                <small><?php the_title(); ?></small>
                            </span>
                        </a>
                    </div>
                    <?php } ?>

                    <h1 class="entry-title">
                    <?php // Check for icon
                        if ( genesis_get_custom_field( '_cmb_project_icon' ) ) { ?>
                    <div class="project-icon">
                            <a href="<?php the_permalink(); ?>" title="<?php the_title(); ?>"><img src="<?php echo genesis_get_custom_field( '_cmb_project_icon' ); ?>" title="<?php the_title();?>" alt="<?php the_title();?>" height="48" width="48" class="the-icon" /></a>
                    </div>
                    <?php } ?>
                        <a href="<?php the_permalink(); ?>" title="<?php the_title(); ?>"><?php the_title(); ?></a></h1>

                    <?php // Check for short description
                        if ( genesis_get_custom_field( '_cmb_project_short_description' ) ) { ?>
                            <div class="project-short-description">
                                <?php echo genesis_get_custom_field( '_cmb_project_short_description' ); ?>
                            </div>
                    <?php } ?>
                    </div>
                    <!-- end .entry-content -->
                </div>
                <!-- end .post -->
    <?php endwhile; wp_reset_query();
}

/** Finish loading the page */
genesis();